Throughout this Annual Report on Form 10-K, the words "we," "us," "our" and "Cytyc" refer to Cytyc Corporation and all of its affiliates and subsidiaries taken as a whole, and "our board of directors" refers to the board of directors of Cytyc Corporation.

Overview of Business

        Cytyc Corporation designs, develops, manufactures, and markets the ThinPrep® System and ThinPrep Imaging System for use in medical diagnostic applications. The ThinPrep System is widely used for cervical cancer screening and non-gynecologic cytology. The ThinPrep System consists of the ThinPrep Pap Test, ThinPrep 2000 Processor, ThinPrep 3000 Processor, and related reagents, filters, and other disposable supplies. The ThinPrep Imaging System, released in June 2003, is a device that uses computer imaging technology to assist in primary cervical cancer screening of ThinPrep Pap Test slides.

        Available Information.     Cytyc files annual, quarterly and current reports, proxy statements and other information with the Securities and Exchange Commission (the "SEC"). You may read and copy any document we file at the SEC's public reference room at Room 1024, 450 Fifth Street, NW, Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for information on the public reference room. The SEC maintains a website that contains annual, quarterly and current reports, proxy statements and other information that issuers (including Cytyc) file electronically with the SEC. The SEC's website is http://www.sec.gov .

        Cytyc's website is located at http://www.cytyc.com . Cytyc makes available free of charge through its internet site its annual reports on Form 10-K; quarterly reports on Form 10-Q; current reports on Form 8-K; and any amendments to those reports filed or furnished pursuant to the Securities Exchange Act of 1934 (the "Exchange Act") as soon as reasonably practicable after such material is electronically filed with, or furnished to, the SEC. The information on Cytyc's website is not incorporated by reference into this report.

        Incorporation.     Cytyc was incorporated in Delaware in 1987.

Cervical Cancer and the Conventional Pap Smear

        Cervical cancer is one of the most common cancers among women throughout the world. If detected in the precancerous stage, virtually all cervical cancer cases are preventable. The treatment of cervical cancer after it reaches the invasive stage may require surgery, including a hysterectomy, and chemotherapy or radiation treatment, which are difficult, expensive and may not be successful.

        Cervical cancer screening has been conducted since the late 1940s using the conventional Pap smear. In the United States, widespread and regular use of the conventional Pap smear as a screening test during the past 60 years has contributed to a greater than 70% decrease in mortality from cervical cancer. The Pap test is currently the most widely used screening test for the early detection of cervical cancer in the United States. It is estimated that over 110 million Pap tests are performed annually worldwide, with over 50 million of those being performed in the United States.

The ThinPrep System and ThinPrep Imaging System

        The ThinPrep System for cervical cancer screening is a replacement for the conventional Pap smear method and was approved by the United States Food and Drug Administration ("FDA") in 1996 as being significantly more effective in detecting low grade and more severe lesions than the conventional Pap smear method in a variety of patient populations. Our clinical trial data also indicates a 59.7% increase in the detection of high grade lesions with the ThinPrep System. The ThinPrep System offers significantly

3

improved specimen quality over that of the conventional Pap smear method. We believe that the ThinPrep System improves accuracy in the detection of cervical cancer and precancerous lesions by making the slide, on which the patient's cell sample is deposited, more uniform and more representative of a patient's clinical condition. The ThinPrep System improves preservation of the sample, standardizes the presentation of cells on the slide in a thin layer of cervical cells and reduces the presence of mucus, blood and other obscuring debris. The ThinPrep System has been approved for use with both broom-like or combined endocervical brush and spatula sampling devices.

        The ThinPrep System consists of a ThinPrep Processor and related disposable reagents, filters and other disposable supplies (together, the disposable supplies used in gynecological applications of the ThinPrep System are referred to as the ThinPrep Pap Test). The ThinPrep Processor is used to prepare microscope slide specimens from preserved patient cell samples for analysis by a cytotechnologist or cytopathologist. We currently offer two types of ThinPrep Processors to laboratory customers: the ThinPrep 2000 Processor, our primary processor, which is a table top device that processes one sample at a time and is capable of processing both gynecological and non-gynecological samples; and the ThinPrep 3000 Processor, our batch processor, which can be loaded with up to 80 ThinPrep Pap Test samples for automatic processing. As of December 31, 2003, we had over 2,700 ThinPrep Processors installed worldwide. The ThinPrep Pap Test is covered by most health plans in the United States.

        The ThinPrep System also serves as a platform for additional gynecological applications using residual patient specimen collected in ThinPrep PreservCyt® Solution. We have obtained FDA approval for PreservCyt Solution to be used as a transport medium in testing for the sexually transmitted diseases Chlamydia trachomatis and Neisseria gonorrhea directly from the ThinPrep Pap Test vial using Roche Diagnostics Corporation's ("Roche") COBAS Amplicor™ automated system. We have also obtained FDA approval for PreservCyt Solution to be used as a transport medium in testing for the human papillomavirus ("HPV") using Digene Corporation's ("Digene") Hybrid Capture® II HPV DNA Assay.

        The ThinPrep Imaging System, which was approved by the FDA in June 2003, is a device that uses computer imaging technology to assist in primary cervical cancer screening of ThinPrep Pap Test slides. The system combines imaging technology to identify diagnostic fields of interest with an automated microscope to facilitate locating these fields. The system is expected to increase a cytology laboratory's screening productivity and diagnostic accuracy while leveraging the increased sensitivity of the ThinPrep Pap Test.

The ThinPrep Process

        The ThinPrep process begins with the patient's cervical sample being taken by the physician using a cervical sampling device that, rather than being smeared on a microscope slide as in a conventional Pap smear, is rinsed in a vial filled with our proprietary PreservCyt Solution. This enables virtually all of the patient's cell sample to be preserved before the cells can be damaged by air drying. The ThinPrep specimen vial is then labeled and sent to a laboratory equipped with a ThinPrep Processor for slide preparation.

        At the laboratory, the ThinPrep specimen vial is inserted into a ThinPrep Processor, a proprietary sample preparation device which automates the process of preparing cervical specimens. Once the vial is inserted into the ThinPrep Processor, a dispersion step breaks up blood, mucus, non-diagnostic debris and large sheets of cells and homogenizes the cell population. The cells are then automatically collected onto our proprietary ThinPrep Pap Test Filter, which incorporates a porous membrane specifically designed to collect cells. The ThinPrep Processor constantly monitors the rate of flow through the ThinPrep Pap Test Filter during the cell collection process in order to prevent the cellular concentration from being too scant or too dense. A thin layer of cells is then transferred from the filter to a glass slide in a 20 mm-diameter circle and the slide is automatically deposited into a fixative solution. This slide is then available for microscopic examination.

4

        The cytotechnologist manually screens each Pap test slide with a microscope to first determine the adequacy of the slide and to then differentiate diseased or abnormal cells from healthy cells. With the introduction of the ThinPrep Imaging System, the screening process has been automated to leverage the combination of computer imaging technology and human interpretive skills. The cytotechnologist places a slide into the ThinPrep Imaging System review scope which automatically presents each area of interest to the cytotechnologist in geographic order. The ThinPrep Imaging System rapidly scans and locates areas of interest for every ThinPrep Pap Test slide. The cytotechnologist evaluates each area of interest, selecting those areas which require further pathologist review, or the cytotechnologist can determine that the slide is negative and simply sign the case out. By directing the cytotechnologist to areas of interest on a slide, the system is expected to increase a cytology laboratory's screening productivity and diagnostic accuracy.

        Our proprietary reagents and supplies include PreservCyt Solution to collect and transport cervical samples to the laboratory for optimal cell preservation and ThinPrep Pap Test Filters to reduce non-diagnostic debris and mucus and collect cells. We also sell ThinPrep Microscope Slides, high-quality microscope slides manufactured to our specifications, which improve cell adhesion to the slide.

Clinical Studies Evaluating the ThinPrep Pap Test

        Since FDA approval, a number of studies have been published or presented that evaluate the ThinPrep Pap Test. To date, more than 50 major studies evaluating the performance of the ThinPrep Pap Test compared to the conventional Pap smear have been published in peer-review journals. The studies have included more than 500,000 patients in the ThinPrep Pap Test cohort and have been conducted in every region of the United States, as well as Europe, Asia, Central America and Australia. The studies consistently demonstrate significant increases in the detection of precancerous cervical lesions. Of particular importance is the number of studies demonstrating statistically significant increases in the detection of high-grade cervical lesions, which are the immediate precursors to cervical cancer. In total, more than 100 studies have been published, in more than 20 separate journals, demonstrating a wide range of benefits including increased disease detection, reduction of equivocal diagnoses and false negatives, improved specimen adequacy, adjunctive molecular testing, morphology assessment, and cost effectiveness.

Non-Gynecological Cytology

        In addition to acting as a replacement for the conventional Pap smear, the ThinPrep System also offers significant improvements for non-gynecological cytology screening applications. Non-gynecological cytology applications include fine-needle aspiration specimens (e.g. breast, thyroid, lung or liver), lavage specimens (e.g. breast, gastrointestinal), body fluids (e.g. urine, pleural fluid, ascitic fluid, pericardial fluid), respiratory specimens (e.g. sputum, brushing of respiratory tracts) and ancillary testing (e.g. cell blocks, immunocytochemistry, special stains). The ThinPrep System provides significant improvements over other methods of non-gynecological cytology screening by optimizing cell preservation through use of our CytoLyt and PreservCyt Solutions, standardizing preparation of specimens using the gentle dispersion and transfer process of the ThinPrep 2000 Processor, simplifying slide screening by offering one single, well-preserved slide per case and allowing laboratories to perform additional ancillary testing out of one PreservCyt Solution vial.

FirstCyte™ Breast Test

        In November 2001, we acquired Pro Duct Health, Inc. ("Pro Duct"), which developed proprietary technology for performing ductal lavage, a test that obtains cells from the breast ducts for laboratory assessment. Using this technology, we introduced the FirstCyte Breast Test, which is currently used as a risk assessment tool for women who are at high risk for breast cancer. The test is used to detect atypical changes in cells lining the milk ducts, where an estimated 95 percent of all breast cancers originate. Breast cancer is a progressive disease. By identifying high risk women who are harboring atypical ductal epithelial

5

cells and who are apparently at highest risk for developing breast cancer, the FirstCyte Breast Test assists in decision making about appropriate preventative measures and enables doctors to move to a paradigm of predicting and preventing breast cancer, rather than the current paradigm of detection and treatment. The FirstCyte Breast Test can be performed by trained obstetrician/gynecologists, radiologists or breast surgeons and is to be used in conjunction with mammography, clinical exams, breast self-exams and other standard breast cancer detection methods. Our existing ThinPrep System can serve as a laboratory platform for preparing the cell sample from the FirstCyte Breast Test, which is a form of non-gynecological cytology screening.

        We are currently planning an outcomes study of the FirstCyte Breast Test to define the value of ductal lavage cytology in high-risk women. In this Serial Evaluation of Ductal Epithelium ("SEDE") trial, high risk women will undergo a ductal lavage every six months for three years. We will follow these women for a period of two years following the initial three years of active enrollment and the result is expected to be a statistically valid understanding of the value of benign cytologic results in high risk women. This study should also clarify the predictive value of an abnormal result from the ductal lavage test. We believe that our investment in this large multi-institutional control study will build the foundation necessary for widespread adoption of the FirstCyte Breast Test. As a result, we have reduced our sales and marketing efforts for the FirstCyte Breast Test as we await the results of the SEDE trial to support significant commercialization of this product.

UroCyte™ Slide Preparation System

        In December 2003, we entered into a collaboration and co-promotion agreement with Abbott Laboratories ("Abbott") for the development and marketing of our ThinPrep UroCyte Slide Preparation System. Initial efforts will focus on modifying our proprietary ThinPrep sample preparation technology to be used in conjunction with Abbott's UroVysion™, a DNA probe-based test for detection of bladder cancer recurrence.

Research and Development

        Our core research and development strategy is to continue to develop innovative medical diagnostic applications of the ThinPrep System and to enhance the ThinPrep Imaging System released in June 2003. Consistent with this strategy, we are currently evaluating additional diagnostic applications of our ThinPrep technology in testing for the presence of other types of cancers and sexually transmitted diseases.

        In addition to internal research and development projects, in 2003 we initiated certain collaborative research agreements with leading institutions. Specifically, in May 2003, we entered into a multi-year collaborative sponsored research agreement with Harvard Medical School focused on the discovery of new molecular markers associated with the development and progression of neoplasia of the cervix, breast, and other organs. In June 2003, we also entered into a collaborative sponsored research agreement with Northeastern University focused on identifying potential breast cancer markers in ductal lavage fluid collected with the FirstCyte Breast Test. Cytyc scientists will work collaboratively with Harvard and Northeastern researchers to translate their findings into further enhancements of Cytyc's testing platforms.

        There can be no assurance that we will be successful in developing or marketing additional applications of the ThinPrep System or that we will further enhance the ThinPrep Imaging System. Furthermore, additional applications may require additional approvals from the FDA prior to the marketing of such applications. There can be no assurance that the FDA would approve such submissions on a timely basis, if at all.

        Our expenditures for research and development totaled approximately $14.7 million, $14.5 million and $19.0 million, for the years ended December 31, 2003, 2002 and 2001, respectively. Research and development for 2001 excludes a one-time charge of $56.0 million for in-process research and development related to the Pro Duct acquisition.

6

Business Development

        We are continually evaluating a variety of new business opportunities that would take advantage of our existing technology and distribution channel. We believe diagnostic tests and devices, particularly those for breast, ovarian, colon, bladder, prostate, and lung cancers, represent growth opportunities. Business opportunities in this area include direct funding of research projects, equity investments or acquisitions to provide new technologies and/or product offerings.

Marketing and Sales

Domestic

        Our marketing and sales strategy is to achieve broad market acceptance of the ThinPrep System and ThinPrep Imaging System for cervical cancer screening and other diagnostic applications. A critical element of our strategy in the United States is to utilize the results of our clinical trials and expanded FDA labeling to demonstrate the safety and efficacy of the ThinPrep System and ThinPrep Imaging System to healthcare providers, clinical laboratories and third-party payors.

        We expect to continue to expand our market reach through marketing by our direct sales force in the United States of over 200 customer and technical service representatives focused on healthcare providers, clinical laboratories and third-party payors. We are focusing significant sales and marketing efforts towards the commercialization of the ThinPrep Imaging System, following its approval by the FDA in June 2003. We expect to use our existing relationships with customers, healthcare providers and third-party payors to successfully market the ThinPrep Imaging System.

        In prior periods, we have entered into certain marketing relationships with third parties, all of which either have expired and have not been renewed or have been terminated for various reasons. In January 2001, we entered into an exclusive agreement in the United States and Puerto Rico with Digene to co-promote the benefits of testing for HPV using Digene's Hybrid Capture II HPV DNA Assay directly from the ThinPrep collection vial. The agreement with Digene expired in June 2003 and we did not seek its renewal.

International

        Our international strategy is to establish selling channels appropriate for increasing our international customer base, taking into consideration factors such as government regulations, screening cycles and clinical practices of the particular country or region. To accomplish this, we have established subsidiaries in six European countries, which we believe represent a large market opportunity. In addition, we have subsidiaries in Australia and Hong Kong, as well as a branch office in Japan. These entities have been established to handle sales, service, training and distribution to clinical laboratories in European and Asian markets. We also utilize a network of third-party distributors to offer our products in various other countries throughout the world.

        In October 2003, the United Kingdom's ("UK") National Institute for Clinical Excellence ("NICE") issued guidance recommending that liquid-based cytology be used as the primary means to process samples for cervical cancer screening programs in England and Wales. NICE, a part of the UK National Health Service ("NHS"), is an independent organization responsible for providing national guidance on treatments and care for those using the NHS in England and Wales. The NHS Cervical Screening Programme and Cervical Screening Wales provide cervical cancer screening for approximately 4.5 million women annually. As a result of this decision, we expect the adoption of the ThinPrep Pap Test to increase in England and Wales. This development follows the announcement in March of 2003 by the Scottish government that it was making a major investment in Scottish cervical screening programs to implement liquid-based cytology. We currently have a multi-year agreement with the Scottish government and Scotland is currently in the process of converting exclusively to the ThinPrep Pap Test.

7

        We believe that international sales efforts will continue to involve a lengthy process, requiring us to educate healthcare providers, clinical laboratories, government entities and other third-party payors regarding the clinical benefits and cost-effectiveness of the ThinPrep System, ThinPrep Imaging System and any other new products and applications. In order to effectively market the ThinPrep System and ThinPrep Imaging System for cervical cancer screening and any other new products and applications on a worldwide basis, we will need to continue to increase our international marketing and sales capabilities.

Third-Party Reimbursement

        The ThinPrep Pap Test is generally billed by laboratories to third-party payors and results in a higher reimbursement amount for the ThinPrep Pap Test than the current reimbursement paid for conventional Pap smears. Successful sales of the ThinPrep System and ThinPrep Imaging System for cervical cancer screening in the United States and other countries will depend on the availability of adequate reimbursement from third-party payors such as private insurance plans, managed care organizations, Medicare and Medicaid and foreign governmental agencies. Although many health insurance companies have added the ThinPrep Pap Test to their payment systems, there can be no assurance that third-party payors will provide or continue to provide such coverage, that reimbursement levels will be adequate or that health care providers or clinical laboratories will use the ThinPrep System for cervical cancer screening in lieu of the conventional Pap smear method or other methods. In addition, we will need to secure adequate third-party reimbursement for the ThinPrep Imaging System and FirstCyte Breast Test, and any new products we develop or obtain.

        Since January 1, 1998, our laboratory customers have been able to request reimbursement for the ThinPrep Pap Test from health insurance companies and the Centers for Medicare and Medicaid Services ("CMS") using a Current Procedural Terminology ("CPT") code specifically for liquid-based cervical cell specimen preparation. CPT codes are assigned, maintained and revised by the CPT Editorial Board, which is administered by the American Medical Association ("AMA"), and are used in the submission of claims to third-party payors for reimbursement for medical services. CMS has established a national limitation amount for Medicare reimbursement of approximately $28 for the CPT code describing the ThinPrep Pap Test. This is nearly double the national limitation amount for reimbursement of the conventional Pap smear. As of December 31, 2003, based on information provided to us, we believe that all of the health insurance companies that announced coverage of the ThinPrep Pap Test as part of the ThinPrep System, representing over 90% of insured women in the United States, have implemented the CPT code and have established a reimbursement amount.

        A new CPT code was established in 2003 for the screening of liquid-based preparations using an automated system. This new code facilitates the reimbursement process for laboratories screening ThinPrep Pap Test slides utilizing the ThinPrep Imaging System. CMS has established a national limitation amount for Medicare reimbursement of this code at approximately $37. We will be working with individual payors and laboratories to establish the new code and reimbursement levels.

        Effective January 1, 2004, the AMA established a new CPT code for use by laboratories when billing for preparation and screening of non-gynecological samples using methods including the ThinPrep System. CMS has allowed reimbursement for this code at a higher level than for the less specific code that was used previously.

        Lack of or inadequate reimbursement by government and other third-party payors for our products would have a material adverse effect on our business, financial condition and results of operations. Further, outside of the United States, healthcare reimbursement systems vary from country to country, and there can be no assurance that third-party reimbursement will be made available at an adequate level, if at all, for our products under any other reimbursement system.

8

Raw Materials and Manufacturing

        We purchase many of the components and raw materials used in our ThinPrep System, ThinPrep Imaging System and the FirstCyte Breast Test from numerous suppliers in the U.S. and abroad. In some cases, we have established long-term supply contracts with our suppliers. For reasons of quality assurance, sole source availability or cost effectiveness, certain components and raw materials are available only from a sole supplier. We work closely with our suppliers to assure continuity of supply while maintaining high quality and reliability. Due to the FDA's requirements regarding manufacture of our products, we may not be able to quickly establish additional or replacement sources for certain components or materials. Generally, we have been able to obtain adequate supplies of such raw materials and components. In the event that we are unable to obtain sufficient quantities of raw materials or components on commercially reasonable terms or in a timely manner, we would not be able to manufacture our products on a timely and cost-competitive basis, which would have a material adverse effect on our business, financial condition and results of operations.

        We assemble all ThinPrep Processors and ThinPrep Imaging Systems, as well as manufacture filters, at our facility in Boxborough, Massachusetts. We fill all of our vials at our facility in Londonderry, New Hampshire. We are currently in the process of transferring certain manufacturing equipment to our facility in Londonderry, New Hampshire, to allow us to manufacture filters in separate locations. We expect this move will be completed in the first half of 2004.

Quality Management

        We place significant emphasis on providing quality products and services to our customers. A major portion of our quality systems relate to the design and development, manufacturing, packaging, sterilization, handling, distribution and labeling of our products. These quality systems, including control procedures that are developed and implemented by technically trained professionals, result in rigid specifications for product design, raw materials, components, packaging materials, labels, sterilization procedures and overall manufacturing process control. Our quality systems integrate the efforts of suppliers of raw materials, components and finished goods to ensure we meet customer and regulatory requirements. These systems are designed to ensure that appropriate standards and requirements are met before goods are released.

        Certain of our facilities are certified under ISO 9001, an international quality standard. In October 2002, we successfully completed inspection by the National Standards Authority of Ireland, which certified our quality control system for compliance with ISO 13485, ensuring compliance with Canadian Medical Device Regulations and replacement of EN 46001 in Europe. There can be no assurance that we will be able to maintain compliance with ISO requirements or that failure to maintain compliance with these requirements will not have a material adverse effect upon our business, financial condition and results of operations.

Government Regulation

        The manufacture and sale of medical diagnostic devices intended for commercial use are subject to extensive governmental regulation in the United States and in other countries. Our existing products are regulated in the United States as medical devices by the FDA under the Federal Food, Drug, and Cosmetic Act ("FDC Act"). The ThinPrep System and ThinPrep Imaging System required separate premarket application ("PMA") approval prior to commercial distribution, which demonstrated to the FDA that the ThinPrep System and ThinPrep Imaging System are safe and effective for their intended uses. The devices which comprise the FirstCyte Breast Test required the filing of 510(k) submissions prior to commercial distribution, which demonstrated that the devices are substantially equivalent to legally marketed devices that are not subject to PMA approval. Pursuant to the FDC Act, the FDA regulates the research, testing, manufacture, safety, labeling, storage, record keeping, advertising, distribution and production of medical

9

devices in the United States. Non-compliance with applicable requirements of the FDC Act can result in the failure of the government to approve 510(k) clearance or PMA approval for a device, withdrawal of clearances or approvals, total or partial suspension of production, fines, injunctions, civil penalties, recall or seizure of products, and criminal prosecution.

        The FDA's regulations may require agency approval of a PMA supplement or a new 510(k) notification for certain changes if they affect the safety and effectiveness of the device, including, but not limited to, new indications for use; labeling changes; the use of a different facility or establishment to manufacture, process, or package the device; changes in manufacturing facilities, methods, or quality control systems; and changes in performance or design specifications.

        The regulatory approval process can be expensive, lengthy and uncertain. There can be no assurance that we will be able to obtain necessary regulatory clearances or approvals for any proposed future products or modifications of existing products. The failure to obtain clearances or approvals, loss of previously received approvals, or failure to comply with existing or future regulatory requirements, would have a material adverse effect on our business, financial condition and results of operations.

        The ThinPrep System for cervical cancer screening received PMA approval in May 1996. In November 1996, the FDA approved expanded product labeling for the ThinPrep System to include the claim that the ThinPrep System is significantly more effective in detecting Low-Grade Squamous Intraepithelial Lesions and more severe lesions than the conventional Pap smear method in a variety of patient populations. The FDA also approved expanded product labeling to include a claim that the specimen quality using the ThinPrep System is significantly improved over that of the conventional Pap smear method. In February 1997, the FDA approved our PMA supplement application for use of a combination of an endocervical brush and spatula sampling devices. In September 1997 and March 1999, the FDA approved our PMA supplement applications for the testing for HPV directly from a single vial of patient specimen collected in ThinPrep solution using Digene's Hybrid Capture and Hybrid Capture II HPV DNA Assay, respectively. In May 2000, the FDA approved the ThinPrep 3000 Processor, our batch processor for automated sample preparation. In August 2001, the FDA approved our PMA supplement application for the inclusion of data describing the detection of High-Grade Squamous Intraepithelial Lesions with the ThinPrep Pap Test. In June 2002, the FDA approved our PMA supplement application to allow for testing for Chlamydia trachomatis and Neisseria gonorrhea directly from the ThinPrep Pap Test vial using Roche's COBAS Amplicor automated system. In June 2003, the FDA approved our PMA application for the ThinPrep Imaging System. We anticipate that any other proposed uses for the ThinPrep System and ThinPrep Imaging System would likely require approval of a PMA supplement or a new PMA application.

        The ThinPrep System and ThinPrep Imaging System are, and any other products we may manufacture or distribute pursuant to an approved PMA application or supplements will be, subject to pervasive and continuing regulation by the FDA, including the Quality System Regulation, or QSR, which requires manufacturers to follow elaborate design, testing, control, documentation and other quality assurance procedures; labeling regulations; the FDA's general prohibition against false or misleading statements in the labeling or advertising products for unapproved or "off-label" uses; the Reports of Corrections and Removals regulation, which requires that manufacturers report to the FDA recalls and field corrective actions taken to reduce a risk to health or to remedy a violation of the FDC Act that may pose a risk to health; and the Medical Device Reporting regulation, which requires that manufacturers report to the FDA if their device may have caused or contributed to a death or serious injury or malfunctioned in a way that would likely cause or contribute to a death or serious injury if it were to recur. We are subject to inspection and marketing surveillance by the FDA to determine our compliance with regulatory requirements. Product labeling, advertising and promotional activities are also subject to scrutiny by the FDA and, in certain instances, by the Federal Trade Commission. Products may only be promoted by us and any of our distributors for their approved indications. No assurance can be given that modifications to the labeling which may be required by the FDA in the future will not adversely affect our ability to market

10

or sell the ThinPrep System, ThinPrep Imaging System, the FirstCyte Breast Test, or any other products we may develop or obtain.

        We are also subject to various federal and state laws pertaining to health care fraud and abuse, including federal and state anti-kickback laws. Anti-kickback laws make it illegal for an entity to solicit, offer, receive, or pay remuneration in exchange for, or to induce, the referral of business or the purchasing, leasing, ordering, or arranging for or recommending the purchase, lease or order of any item or service paid for by Medicare, Medicaid or certain other federal health care programs. The statute has been broadly interpreted to cover a wide array of practices. Some states have passed similar laws. The federal government has published regulations that identify "safe harbors," which if applicable will assure that certain arrangements will not be found to violate the federal anti-kickback statutes. Our activities relating to the sale and marketing of our products may be subject to scrutiny under these laws. While we make every effort to comply with the regulations, it is possible that our practices might be challenged under federal anti-kickback or similar laws due to the breadth of the statutory provisions and the absence of extensive guidance. Violations of fraud and abuse laws may be punishable by criminal and/or civil sanctions, including fines and civil monetary penalties, as well as the possibility of exclusion from federal health care programs (including Medicare and Medicaid). If the government were to raise questions about our behavior or find that we have violated these laws, there could be a material adverse effect on our business, including our stock price. Our activities could be subject to challenge for the reasons discussed above, due to the broad scope of these laws and the increasing attention being given to them by law enforcement authorities.

        We also are subject to numerous federal, state and local laws relating to such matters as safe working conditions, manufacturing practices, environmental protection, fire hazard control and disposal of hazardous or potentially hazardous substances. There can be no assurance that we will not be required to incur significant costs to comply with such laws and regulations in the future, or that such laws or regulations will not have a material adverse effect upon our business, financial condition and results of operations.

        Sales of medical devices outside of the United States are subject to foreign regulatory requirements that vary widely from country to country. In 2003, we met the essential requirements of the European In Vitro Medical Devices Directive ("IVDD") that apply to the ThinPrep Pap Test and ThinPrep Imaging System, as well as the essential requirements of the European Medical Devices Directive ("MDD") that apply to the FirstCyte Breast Test. As a result, Cytyc's products bear the CE mark and may be legally marketed in the countries of the European Union and the European Free Trade Association. The time required to obtain approval from a foreign country to market and sell the ThinPrep System, ThinPrep Imaging System and FirstCyte Breast Test may be longer or shorter than that required for FDA approval and the requirements may differ. No assurance can be given that such foreign regulatory approvals will be granted on a timely basis, or at all. In addition, there can be no assurance that we will meet the FDA's export requirements or receive FDA export approval when such approval is necessary, or that countries to which the devices are to be exported will approve the devices for import. Our failure to meet the FDA's export requirements or obtain FDA export approval when required to do so, or to obtain approval for import, could have a material adverse effect on our business, financial condition and results of operations.

        The laboratories that purchase the ThinPrep System and ThinPrep Imaging System are subject to extensive regulation under the Clinical Laboratory Improvement Amendments of 1988 ("CLIA"), which require laboratories to meet specified standards in the areas of personnel qualifications, administration, participation in proficiency testing, patient test management, quality control, quality assurance and inspections. We believe that the ThinPrep System and ThinPrep Imaging System operate in a manner that will allow laboratories purchasing the device to comply with CLIA requirements. However, there can be no assurance that adverse interpretations of current CLIA regulations or future changes in CLIA regulations would not have an adverse effect on sales of the ThinPrep System and ThinPrep Imaging System.

11

Patents, Trademarks, Copyrights, Licenses and Proprietary Rights

        We rely on a combination of patents, trademarks, trade secrets, copyrights and confidentiality agreements to protect our proprietary technology, rights and know-how. We pursue patent protection in the United States and file corresponding patent applications in certain foreign jurisdictions. We hold 36 issued United States patents, 54 pending United States patent applications, and corresponding foreign patents or patent applications relating to various aspects of our ThinPrep System, ThinPrep Imaging System, FirstCyte Breast Test and other related technologies. There can be no assurance, however, that pending patent applications will ultimately issue as patents or that the claims allowed in any of our existing or future patents will provide competitive advantages for our products or will not be successfully challenged or circumvented by competitors. We cannot be sure that our products or technologies do not infringe patents that may be granted in the future pursuant to pending patent applications or that our products do not infringe any existing patents or proprietary rights of third parties. In the event that any relevant claims of third-party patents are successfully enforced against us, we could be prevented from selling our products or could be required to obtain licenses from the owners of such patents or be required to redesign our products to avoid infringement. There can be no assurance that such licenses would be available or, if available, would be on terms acceptable to us or that we would be successful in any attempts to redesign our products or processes to avoid infringement. Our failure to obtain these licenses or to successfully redesign our products would have a material adverse effect on our business, financial condition and results of operations.

        Our employees and third parties with whom we have entered into confidentiality agreements are obligated to maintain the confidentiality of our trade secrets and proprietary information. There can be no assurance that such obligations will effectively prevent disclosure of our confidential information or provide meaningful protection for our confidential information if there is unauthorized use or disclosure. At the same time, technology similar to ours may be independently developed by our competitors.

        We are the exclusive perpetual worldwide licensees of certain patented technology from DEKA Products, LP ("DEKA"). In addition, we are the exclusive licensee of certain patented technology from the Regents of the University of California for use in the field of diagnosis and treatment of breast cancer. We also hold unregistered copyrights on internally developed documentation and operating software developed for the ThinPrep System and ThinPrep Imaging System. We currently are obligated to pay royalties in varying amounts to these parties. Our failure to maintain rights to such technology could have a material adverse effect on our business, financial condition and results of operations. In November 2003, DEKA filed a demand for arbitration with the American Arbitration Association alleging that we have underpaid royalties, a claim which we dispute. See "Item 3. Legal Proceedings" for a discussion of this matter. We presently have several trademarks, some of which have been registered with the United States Patent and Trademark Office. There can be no assurance that any copyrights or trademarks we own will provide competitive advantages for our products or will not be challenged or circumvented by our competitors.

        Litigation may be necessary to defend against claims of infringement, or to enforce our patents, copyrights, trademarks or trade secrets which could result in substantial cost to us and diversion of focus away from our business. In addition, the laws of some foreign countries do not protect our proprietary rights to the same extent as do the laws of the United States.

Customers and Competition

        Quest Diagnostics, Inc. ("Quest") and Laboratory Corporation of America ("LabCorp") accounted for 22% and 10% of our consolidated net sales, respectively, for the year ended December 31, 2003. Quest and LabCorp accounted for 20% and 13% of our consolidated net sales, respectively, for the year ended December 31, 2002. Quest represented 20% of our consolidated net sales for the year ended December 31, 2001. During 2001, no other customers represented 10% or more of consolidated net sales.

12

        While we are the market leader in the sale of liquid-based slide preparation systems in the United States, we face direct competition in the United States from TriPath Imaging, Inc., which also manufacturers liquid-based slide preparation systems. We also compete with the conventional Pap smear and other alternative methods for detecting cervical cancer and/or its precursors. We compete on the basis of a number of factors, including clinical performance, product quality, marketing and sales capabilities, manufacturing efficiency, price and customer service and support. The development, FDA approval and commercial marketing of competing systems for cervical cancer screening could have a material adverse effect on our business, financial condition and results of operations.

Seasonality

        Seasonality does not have a significant impact on our worldwide sales.

Employees

        As of December 31, 2003, we employed 723 persons worldwide. We are not subject to any collective bargaining agreements, have never experienced a work stoppage and consider our relations with our employees to be good.

Financial Information Regarding Segment Reporting and Geographic Areas

        We currently operate in one segment, medical diagnostic equipment. Please refer to Note 2(t) "Segment and Enterprise-Wide Reporting" in the notes to consolidated financial statements included in this Annual Report on Form 10-K under Item 8, "Financial Statements and Supplementary Data."

Certain Factors Which May Affect Future Results

        The following factors, among others, could cause actual results to differ materially from those contained in forward-looking statements made in this report and presented elsewhere by management from time to time. Such factors, among others, may have a material adverse effect upon our business, financial condition, and results of operations.

        The following discussion of our risk factors should be read in conjunction with the consolidated financial statements and related notes included herein. Because of these and other factors, past financial performance should not be considered an indication of future performance.

We depend principally on the sale of a single product.

        To date, we have derived most of our revenues from sales of our ThinPrep 2000 Processor, filters, and other disposable supplies for use in gynecological and non-gynecological testing applications. If we are unable to successfully develop and commercialize other products, our business, sales and profits will be materially impaired. Although we have begun marketing our ThinPrep 3000 Processor, ThinPrep Imaging System and FirstCyte Breast Test, we have not yet generated significant revenues from these products. We cannot guarantee that we will be able to obtain adequate reimbursement from insurance companies and other third party payors for the ThinPrep Imaging System and FirstCyte Breast Test, or that we will otherwise be able to generate significant revenue from sales of these products. We may be required to obtain FDA approval and secure adequate reimbursement from insurance companies and other third party payors for any other new products that we are able to develop or acquire, and we may not be able to do so.

13

We cannot guarantee we will obtain necessary regulatory approvals for our products.

        If we do not obtain all necessary regulatory approvals for any new products we are able to successfully develop or acquire, our ability to generate sales from new product offerings will materially suffer. The governments of the United States and other countries extensively regulate the manufacture and sale of medical diagnostic devices intended for commercial use. For example, United States commercial distribution of medical diagnostic devices generally requires FDA clearance or approval before selling may commence. Obtaining FDA and other required regulatory approvals can be time-consuming, expensive and uncertain. Regulatory approval frequently requires several years from the commencement of clinical trials to the receipt of regulatory approval. After any approvals, we remain subject to pervasive regulation and inspection for ongoing compliance with regulatory requirements. We may also need to obtain FDA approval for any other new products we are able to develop or acquire, and we cannot guarantee that we will be able to do so.

Our success depends on the market acceptance of our products and their cost.

        Our success and growth depends primarily on market acceptance of our ThinPrep System and ThinPrep Imaging System, including any follow-on applications of ThinPrep technology, such as the FirstCyte Breast Test. The laboratory cost of using the ThinPrep System and ThinPrep Imaging System for cervical cancer screening, both together and individually, is higher than that of a conventional Pap smear and competing liquid-based slide preparation systems. Due in part to increased competitive pressures in the healthcare industry to reduce costs, our ability to gain market acceptance of the ThinPrep System and follow-on products depends on our ability to demonstrate that the higher cost of using the ThinPrep System is offset by (i) a reduction in costs often associated with conventional Pap smears or competing liquid-based slide preparation systems, such as inaccurate diagnoses and the need for repeat Pap smears, as well as (ii) the ability to use our ThinPrep System for additional testing applications, such as testing for the human papillomavirus ("HPV"), Chlamydia trachomatis and Neisseria gonorrhea . In particular, for both the ThinPrep Imaging System and the FirstCyte Breast Test, we need to convince healthcare providers, insurance companies and other third party payors, and clinical laboratories of the clinical benefits and cost-effectiveness of these products. For the FirstCyte Breast Test, we await the results of the SEDE trial to support market acceptance of this product and its cost.

Some of our activities may subject us to risks under federal and state laws prohibiting "kickbacks" and false or fraudulent claims.

        We are subject to the provisions of a federal law commonly known as the Medicare/Medicaid anti-kickback law, and several similar state laws, which prohibit payments intended to induce physicians or others either to refer patients or to acquire or arrange for or recommend the acquisition of health care products or services. While the federal law applies only to referrals, products or services for which payment may be made by a federal health care program, state laws often apply regardless of whether federal funds may be involved. These laws constrain the sales, marketing and other promotional activities of manufacturers of medical devices, such as us, by limiting the kinds of financial arrangements, including sales programs, with hospitals, physicians, laboratories and other potential purchasers of medical devices. Other federal and state laws generally prohibit individuals or entities from knowingly presenting, or causing to be presented, claims for payment from Medicare, Medicaid, or other third-party payors that are false or fraudulent, or are for items or services that were not provided as claimed. Anti-kickback and false claims laws prescribe civil and criminal penalties for noncompliance that can be substantial. While we continually strive to comply with these complex requirements, interpretations of the applicability of these laws to marketing practices is ever evolving and even an unsuccessful challenge could cause adverse publicity and be costly to respond to, and thus could have a material adverse effect on our business, results of operations and financial condition.

14

Our sales are dependent on third-party reimbursement.

        Widespread adoption of our ThinPrep System, ThinPrep Imaging System and the FirstCyte Breast Test in the United States and other countries is dependent upon the ability of healthcare providers and laboratories to secure adequate reimbursement from third-party payors such as private insurance plans, managed care organizations, and Medicare and Medicaid. Although a majority of managed care organizations in the United States have added the ThinPrep Pap Test to their coverage, we cannot guarantee that reimbursement will increase or continue to be available, or that reimbursement levels will be adequate to enable healthcare providers and clinical laboratories in the United States and other countries to use the ThinPrep System and ThinPrep Imaging System for cervical cancer screening, instead of the conventional Pap smear method or the products of our competitors. We also will be required to secure adequate reimbursement for any new products we develop or obtain, and we may not be able to do so successfully.

We are dependent upon a relatively small number of large clinical laboratory customers in the United States for a significant portion of our sales.

        We are dependent upon a relatively small number of large clinical laboratory customers in the United States for a significant portion of our sales of the ThinPrep System, and our business may materially suffer if we are unable to increase sales to, or maintain our pricing levels with, our existing customers and establish new customers both within and outside the United States. Due in part to a trend toward consolidation of clinical laboratories in recent years and the relative size of the largest United States laboratories, it is likely that a significant portion of ThinPrep System sales will continue to be concentrated among a relatively small number of large clinical laboratories.

We may engage in acquisitions that may harm our operating results, dilute our stockholders' equity, divert management's attention from other important business concerns, and potentially create other difficulties for us.

        We may in the future pursue acquisitions that we believe could provide us with new technologies, products or service offerings, or enable us to obtain other competitive advantages.

        Acquisitions by us may involve some or all of the following financial risks:

•

use of significant amounts of cash;



•

potential dilutive issuances of equity securities;



•

incurrence of debt or amortization expenses related to certain intangible assets; and



•

future impairment charges related to diminished fair value of businesses acquired as compared to their net book value.

        Such acquisitions also may involve numerous other risks, including:

•

diversion of management's attention from other business concerns;



•

difficulties associated with assimilating and integrating personnel, operations and technologies of acquired companies;



•

failure to retain key personnel;



•

loss of key customers, customer dissatisfaction or performance problems with the acquired company;



•

the costs associated with the integration of acquired operations; and



•

assumption of unknown liabilities.

15

        We may not be successful in overcoming the risks described above or any other problems associated with future acquisitions. Any of these risks and problems could materially harm our business, prospects, and financial condition. Additionally, we cannot guarantee that any companies we may acquire will achieve anticipated revenues and operating results.

Our success depends on our ability to manage growth effectively.

        The scope of our operations and facilities, the number of our employees and the geographic area of our operations are growing rapidly. If we are not able to manage our growth effectively, our business and financial condition will materially suffer. Our growth may significantly strain our managerial, operational and financial resources and systems. To manage our growth effectively, we will have to continue to implement and improve additional management and financial systems and controls, and to expand, train and manage our employee base.

We have intense competition from other companies.

        We face direct competition from a number of publicly-traded and privately-held companies, including manufacturers of liquid-based slide preparation systems. The development, FDA approval and commercial marketing of competitive systems for cervical cancer screening could have a material adverse effect on our business and financial condition.

Product liability suits against us could result in expensive and time-consuming litigation, payment of substantial damages and increases in our insurance rates.

        The sale and use of our products could lead to the filing of product liability claims if someone were to allege that one of our products contained a design or manufacturing defect which resulted in the failure to detect a disorder for which it was being used to screen. A product liability claim could result in substantial damages and be costly and time-consuming to defend, either of which could materially harm our business or financial condition. We cannot assure that our product liability insurance would protect our assets from the financial impact of defending a product liability claim. Any product liability claim brought against us, with or without merit, could increase our product liability insurance rates or prevent us from securing insurance coverage in the future.

Our quarterly operating results may vary.

        Our operating results have fluctuated significantly in the past on a quarterly basis. We expect that our operating results may fluctuate significantly from quarter to quarter and we may experience losses in the future depending on a number of factors, including the extent to which our products continue to gain market acceptance, the rate and size of expenditures incurred as we expand our domestic and establish our international sales and distribution networks, the timing and level of reimbursement for our products by third-party payors, and other factors, many of which are outside our control.

        In addition, the Financial Accounting Standards Board has proposed, and is currently considering, changes to generally accepted accounting principles in the United States that would require us to record a charge to earnings for employee stock option grants. This pending standard would negatively impact our earnings and increase the volatility of our quarterly operating results. For example, recording a charge for employee stock options under Statement of Financial Accounting Standards No. 123, Accounting for Stock-Based Compensation , would have reduced net income by $43.8 million, $54.2 million and $39.4 million for the years ended December 31, 2003, 2002 and 2001, respectively. See also Note 2(r) to the consolidated financial statements—Summary of Significant Accounting Policies: Stock-Based Compensation.

16

We currently have limited foreign sales capabilities and cannot guarantee success in foreign markets.

        Although we commenced sales of our ThinPrep System in countries outside the United States in 1998, only a small percentage of our sales to date have been to international markets. If we fail to increase international sales, our business and financial condition may suffer materially. We cannot guarantee that we will successfully develop foreign sales channels or capabilities that will enable us to generate significant revenue from international sales. Even if we are able to establish foreign sales capabilities, we may not be able to obtain favorable third-party reimbursements and required regulatory approvals in foreign countries. We may also face difficulty and added expense in complying with the U.S. and foreign regulations applicable to the sale and marketing of our products internationally.

We are uncertain if additional applications of our ThinPrep System will be successful.

        In addition to cervical cancer screening, the ThinPrep System serves as a platform for other gynecological applications, including testing for HPV using Digene's Hybrid Capture II HPV DNA Assay and testing for the sexually transmitted diseases Chlamydia trachomatis and Neisseria gonorrhea using Roche's COBAS Amplicor automated system. We intend to continue to evaluate additional uses of our ThinPrep technology in testing for the presence of other types of cancers and sexually transmitted diseases. We have not yet determined which of these additional applications we will seek to develop, commercialize or promote, alone or with other companies. We may not be able to successfully promote, commercialize or develop additional uses of our technology.

We are highly dependent on key personnel.

        We are highly dependent on the principal members of our management staff. Loss of our key personnel would likely impede achievement of our research and development, operational, or strategic objectives. To be successful, we must retain key employees and attract additional qualified employees.

Our success depends on our ability to protect our intellectual property rights.

        We rely on a combination of patents, trade secrets, copyrights, trademarks and confidentiality agreements to protect our proprietary technology, rights and know-how. We also are the exclusive licensee of certain patented technology for use in the field of cytology related to the ThinPrep System and in the field of breast cancer detection and treatment related to the FirstCyte Breast Test. If we fail to protect, defend and maintain our intellectual property rights, or if we are subject to a successful third party claim of infringement or violation of license terms, our business and financial condition will materially suffer.

Our reliance on sole source suppliers could harm our business.

        We currently obtain certain key components of the ThinPrep System and ThinPrep Imaging System, including our propriety filter material, from single sources. If we are unable to obtain sufficient quantities of these components that meet our quality and technical requirements at reasonable prices and in a timely manner, we will not be able to manufacture and sell our products on a timely and cost-competitive basis, which would materially and adversely affect our business and financial condition.

Our lack of redundant manufacturing facilities could harm our business.

        We assemble all of our ThinPrep Processors, the ThinPrep Imaging System and the FirstCyte Breast Test, as well as manufacture filters, at our facility in Boxborough, Massachusetts. We fill all of our vials at our facility in Londonderry, New Hampshire. The loss of any of these facilities would likely impede our manufacturing and sales efforts, which would materially and adversely affect our business and financial condition. We are currently working to establish site redundancy for our facility in Boxborough, Massachusetts. We are also working to establish an additional fill line in our Londonderry, New Hampshire facility but are not planning at this time to establish a redundant site for this facility.

17

18