AIM SECTOR FUNDS

(as Successor to AIM SECTOR FUNDS, INC., formerly named INVESCO SECTOR FUNDS, INC.)

(Exact Name of Registrant as Specified in Charter)

11 Greenway Plaza, Suite 100, Houston, TX 77046

(Address of Principal Executive Offices)

Registrant’s Telephone Number, including Area Code: (713) 626-1919

Robert H. Graham

11 Greenway Plaza, Suite 100

Houston, TX 77046

(Name and Address of Agent for Service)

Approximate Date of Proposed Public Offering: As soon as practicable after this post-effective amendment becomes effective.

It is proposed that this filing will become effective (check appropriate box)

If appropriate, check the following box:

PROSPECTUS | July 30, 2004

INVESCO ENERGY FUND  — INVESTOR CLASS, CLASS A, B, C, AND K

INVESCO FINANCIAL SERVICES FUND  — INVESTOR CLASS, CLASS A, B, C, AND K

INVESCO GOLD & PRECIOUS METALS FUND  — INVESTOR CLASS, CLASS A, B, AND C

INVESCO HEALTH SCIENCES FUND  — INVESTOR CLASS, CLASS A, B, C, AND K

INVESCO LEISURE FUND  — INVESTOR CLASS, CLASS A, B, C, AND K

INVESCO TECHNOLOGY FUND  — INVESTOR CLASS, CLASS A, B, C, AND K

INVESCO UTILITIES FUND  — INVESTOR CLASS, CLASS A, B, AND C

Seven mutual funds designed for investors seeking capital growth through targeted investment opportunities.

Investor Class shares offered by this Prospectus are offered only to grandfathered investors. Please see the section of the Prospectus entitled “How To Buy Shares.”

Class A, B, and C shares are sold primarily through financial intermediaries. Class K shares are sold to qualified retirement plans, retirement savings programs, educational savings programs, and wrap programs primarily through financial intermediaries.

No dealer, salesperson, or any other person has been authorized to give any information or to make any representations other than those contained in this Prospectus, and you should not rely on such other information or representations.

The Securities and Exchange Commission has not approved or disapproved the shares of these Funds. Likewise, the Commission has not determined if this Prospectus is truthful or complete. Anyone who tells you otherwise is committing a federal crime.

AIM SECTOR FUNDS

A I M Advisors, Inc. (“AIM” or the “advisor”) is the investment advisor for each Fund, and INVESCO Institutional (N.A.), Inc.-Denver Division (“INVESCO Institutional” or “sub-advisor”) is the sub-advisor for each Fund. On November 20, 2003, the series portfolios of AIM Sector Funds, Inc., a Maryland corporation (the “Company”), were redomesticated as the Funds, which are series portfolios of AIM Sector Funds, a Delaware statutory trust. INVESCO Institutional is an affiliate of AIM.

This Prospectus contains important information about the Funds’ Investor Class, Class A, B, C, and, if applicable, K shares. Class A, B, and C shares are sold primarily through financial intermediaries. Class K shares are sold to qualified retirement plans, retirement savings programs, educational savings programs, and wrap programs primarily through financial intermediaries. If you invest through a financial intermediary, please contact your financial intermediary or, with respect to Class K shares, your plan or program sponsor, for detailed information on suitability and transactional issues (i.e., how to purchase or sell shares, minimum investment amounts, and fees and expenses). INVESCO Technology Fund also offers an additional class of shares through a separate Prospectus. Each of the Fund’s classes has varying expenses, with resulting effects on their performance. You can choose the class of shares that is best for you, based on how much you plan to invest and other relevant factors discussed in “How To Buy Shares.” To obtain additional information about the other class of Technology Fund’s shares, contact A I M Distributors, Inc. (“ADI”) at 1-800-347-4246.

This Prospectus will tell you more about:

Energy, Financial Services, Health Sciences, Leisure, Technology, and Utilities Funds may invest up to 25% of their respective assets in securities of non-U.S. issuers. Securities of Canadian issuers and American Depositary Receipts are not subject to this 25% limitation. Foreign securities risks are potentially greater for the Gold & Precious Metals Fund, since that Fund has the ability to invest more than 25% of its assets in the securities of non-U.S. issuers.

The sub-advisor uses a research oriented “bottom-up” investment approach to create each Fund’s investment portfolio, focusing on company fundamentals and growth prospects when selecting securities. In general, the Funds emphasize companies that the sub-advisor believes are strongly managed and will generate above-average long-term capital appreciation.

Growth investing may be more volatile than other investment styles because growth stocks are more sensitive to investor perceptions of an issuing company’s growth potential. Growth-oriented funds typically will underperform value-oriented funds when investor sentiment favors the value investing style. Value investing seeks securities, particularly stocks, that are currently undervalued by the market — companies that are performing well, or have solid management and products, but whose stock prices do not reflect that value. Through our value process, we seek to provide reasonably consistent returns over a variety of market cycles. Value-oriented funds typically will underperform growth-oriented funds when investor sentiment favors the growth investing style.

As sector funds, each portfolio is concentrated in a comparatively narrow segment of the economy. This means a Fund’s investment concentration in a sector is higher than most mutual funds and the broad securities markets. Consequently, the Funds tend to be more volatile than other mutual funds, and the value of their portfolio investments and consequently the value of an investment in a Fund tend to go up and down more rapidly.

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The Funds are subject to other principal risks, as applicable, such as market, foreign securities, liquidity, derivatives, counterparty, lack of timely information, and portfolio turnover risks. These risks are described and discussed later in the Prospectus under the headings “Investment Risks” and “Principal Risks Associated With The Funds.” An investment in a Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation (“FDIC”) or any other government agency. As with any mutual fund, there is always a risk that you may lose money on your investment in a Fund.

The Funds are concentrated in these sectors:

The Fund normally invests at least 80% of its net assets in the equity securities and equity-related instruments of companies within the energy sector. These companies include, but are not limited to, oil companies, oil and gas exploration companies, natural gas pipeline companies, refinery companies, energy conservation companies, coal, alternative energy companies, and innovative energy technology companies.

Generally, we prefer to keep the Fund’s investments divided among the four main energy subsectors: major oil companies, energy services, oil and gas exploration/production companies, and natural gas pipeline companies. We adjust portfolio weightings depending on current economic conditions. Although individual security selection drives the performance of the Fund, short-term fluctuations in commodity prices may influence Fund returns and increase price fluctuations in the Fund’s shares. The businesses in which we invest may be adversely affected by foreign government, federal, or state regulations on energy production, distribution, and sale.

The Fund normally invests at least 80% of its net assets in the equity securities and equity-related instruments of companies involved in the financial services sector. These companies include, but are not limited to, banks (regional and money-centers), insurance companies (life, property and casualty, and multiline), investment and miscellaneous industries (asset managers, brokerage firms, and government-sponsored agencies), and suppliers to financial services companies.

We place a greater emphasis on companies that are increasing their revenue streams along with their earnings. We seek companies that we believe can grow their revenues and earnings in a variety of interest rate environments — although securities prices of financial services companies generally are interest rate sensitive. We seek companies with successful sales and marketing cultures and that leverage technologies in their operations and distribution. We adjust portfolio weightings depending on current economic conditions and relative valuations of securities.

This sector generally is subject to extensive governmental regulation, which may change frequently. In addition, the profitability of businesses in these industries depends heavily upon the availability and cost of money, and may fluctuate significantly in response to changes in interest rates, as well as changes in general economic conditions. From time to time, severe competition may also affect the profitability of these industries.

The Fund normally invests at least 80% of its net assets in the equity securities and equity-related instruments of companies involved in exploring for, mining, processing, or dealing and investing in gold, gold bullion, and other precious metals, such as silver, platinum, and palladium, as well as diamonds. The securities of these companies are highly dependent on the price of precious metals at any given time.

Fluctuations in the price of gold directly — and often dramatically — affect the profitability and market value of companies in this sector. Changes in political or economic climate for the two largest gold producers — South Africa and the former Soviet Union — may have a direct impact on the price of gold worldwide. Up to 10% of the Fund’s assets at the time of purchase may be invested in gold bullion. The Fund’s investments directly in gold bullion will earn no income return; appreciation in the market price of gold is the sole manner in which the Fund can realize gains on bullion investments. The Fund may have higher storage and custody costs in connection with its ownership of bullion than those associated with the purchase, holding and sale of more traditional types of investments.

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The Fund primarily focuses on those gold companies that have the ability to increase production capacity at low costs, while having the potential to make major gold discoveries around the world. Additionally, we try to identify companies that leverage increasing gold prices; that is, companies that do not hedge gold prices on the market. While the Fund may take positions in mid- to small-sized exploration companies that may be more volatile than investments in large, more established companies, it will primarily focus on major gold stocks that are leaders in their fields. Up to 100% of the Fund’s assets may be invested in foreign companies.

The Fund normally invests at least 80% of its net assets in the equity securities and equity-related instruments of companies that develop, produce, or distribute products or services related to health care. These companies include, but are not limited to, medical equipment or supplies, pharmaceuticals, biotechnology, and health care providers and services companies.

We focus on the leading players in fast-growing therapeutic areas or companies on the verge of exciting medical breakthroughs. Leading players in the health care industry include companies with strong, commercially successful products as well as promising product pipelines. This strategy may lead us to invest in both well-established health care firms and faster-growing, more dynamic entities. Well-established health care companies typically provide liquidity and earnings visibility for the portfolio and represent core holdings in the Fund. The Fund also may invest in high growth, earlier stage companies whose future profitability could be dependent upon increasing market shares from one or a few key products. Such companies often have limited operating histories and their potential profitability may be dependent on regulatory approval of their products, which increases the volatility of these companies’ securities prices and could have an adverse impact upon the companies’ future growth and profitability.

Changes in government regulation could also have an adverse impact upon the companies’ future growth and profitability. Continuing technological advances may mean rapid obsolescence of products and services.

The Fund normally invests at least 80% of its net assets in the equity securities and equity-related instruments of companies engaged in the design, production, and distribution of products related to the leisure activities. These industries include, but are not limited to, hotels/gaming, publishing, advertising, beverages, audio/video, broadcasting-radio/TV, cable & satellite operators, cable & satellite programmers, motion pictures & TV, recreation services/entertainment, retail, and toys.

We seek firms that can grow their businesses regardless of the economic environment. The sub-advisor attempts to keep the portfolio well diversified across the leisure sector, adjusting portfolio weightings depending on prevailing economic conditions and relative valuations of securities. This sector depends on consumer discretionary spending, which generally falls during economic downturns. Securities of gambling casinos often are subject to high price volatility and are considered speculative. Video and electronic games are subject to risks of rapid obsolescence.

The Fund normally invests at least 80% of its net assets in the equity securities and equity-related instruments of companies engaged in technology-related industries. These include, but are not limited to, various applied technologies, hardware, software, semiconductors, telecommunications equipment and services, and service-related companies in information technology. Many of these products and services are subject to rapid obsolescence, which may lower the market value of the securities of the companies in this sector.

A core portion of the Fund’s portfolio is invested in market-leading technology companies among various subsectors in the technology universe that we believe will maintain or improve their market share regardless of overall economic conditions. These companies are leaders in their field and are believed to have a strategic advantage over many of their competitors. The remainder of the Fund’s portfolio consists of faster-growing, more volatile technology companies that the sub-advisor believes to be emerging leaders in their fields. The market prices of these companies tend to rise and fall more rapidly than those of larger, more established companies.

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The Fund normally invests at least 80% of its net assets in the equity securities and equity-related instruments of companies engaged in utilities-related industries. These include, but are not limited to, companies that produce, generate, transmit, or distribute natural gas or electricity, as well as companies that provide telecommunications services, including local, long distance and wireless.

Governmental regulation, difficulties in obtaining adequate financing and investment return, environmental issues, prices of fuel for generation of electricity, availability of natural gas, risks associated with power marketing and trading, and risks associated with nuclear power facilities may adversely affect the market value of the Fund’s holdings. The recent trend towards deregulation in the utility industries presents special risks. Some companies may be faced with increased competition and may become less profitable.

Normally, the sub-advisor seeks to keep the portfolio divided among the electric utilities, natural gas, and telecommunications industries. Weightings within the various industry segments are continually monitored, and we adjust the portfolio weightings depending on the prevailing economic conditions.

Performance information in the bar charts below is that of the Funds’ Investor Class shares, which have the longest operating history of the Funds’ classes. Information included in the table is that of Investor Class, Class A, B and C shares, and, if applicable, Class K shares. Investor Class and Class A, B, C, and K share returns would be similar because all classes of shares invest in the same portfolio of securities. The returns of the classes would differ, however, to the extent of differing levels of expenses or sales loads. In this regard, the returns reflected in the bar charts reflect only the applicable total expenses of the Investor Class shares. If the effect of the other classes’ total expenses were reflected, the returns would be lower than those shown because the other classes have higher total expenses.

The bar charts below show the Funds’ Investor Class shares actual yearly performance (commonly known as their “total return”) for the years ended December 31 over the past decade or since inception. The returns in the bar charts do not reflect a 12b-1 fee in excess of 0.25% or sales loads; if they did, the total returns shown would be lower. The table below shows the pre-tax and after-tax average annual total returns of Investor Class shares and pre-tax average annual total returns for Class A, B and C shares, and, if applicable, Class K shares for various periods ended December 31, 2003. The after-tax returns are shown only for the Investor Class shares. After-tax returns for other classes of shares offered in this Prospectus will vary.

After-tax returns are provided on a pre-redemption and post-redemption basis. Pre-redemption returns assume you continue to hold your shares and pay taxes on Fund distributions (i.e., dividends and capital gains) but do not reflect taxes that may be incurred upon selling or exchanging shares. Post-redemption returns assume payment of taxes on fund distributions and also that you close your account and pay remaining federal taxes. After-tax returns are calculated using the highest individual federal income tax rates in effect at the time the distribution is paid. State and local taxes are not considered. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. For investors holding their shares in tax-deferred arrangements such as 401(k) plans or individual retirement accounts, the after-tax returns shown are not relevant.

The information in the bar charts and table illustrates the variability of each Fund’s total return. The table shows each Fund’s performance compared to a broad-based securities market index, a style specific index and/or a peer group index. The indices may not reflect payment of fees, expenses or taxes. The fund is not managed to track the performance of any particular index, including the indices shown below, and consequently, the performance of the fund may deviate significantly from the performance of the indices shown below. Remember, past performance (before and after taxes) does not indicate how a Fund will perform in the future.

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     ENERGY FUND — INVESTOR CLASS

ACTUAL ANNUAL TOTAL RETURN ¹

Best Calendar Qtr.      9/97 28.24%

Worst Calendar Qtr.   9/98 (18.34%)

     FINANCIAL SERVICES FUND — INVESTOR CLASS

ACTUAL ANNUAL TOTAL RETURN ¹

Best Calendar Qtr.      9/00  22.76%

Worst Calendar Qtr.   9/98 (18.20%)

GOLD & PRECIOUS METALS FUND —

INVESTOR CLASS

ACTUAL ANNUAL TOTAL RETURN ¹

Best Calendar Qtr.      3/96  46.17%

Worst Calendar Qtr.   12/97 (37.51%)

HEALTH SCIENCES FUND — INVESTOR CLASS

ACTUAL ANNUAL TOTAL RETURN ¹

Best Calendar Qtr.      9/95  19.54%

Worst Calendar Qtr.   3/01 (22.91%)

LEISURE FUND — INVESTOR CLASS

ACTUAL ANNUAL TOTAL RETURN ¹

Best Calendar Qtr.      12/99  25.59%

Worst Calendar Qtr.   9/01 (24.06%)

TECHNOLOGY FUND — INVESTOR CLASS

ACTUAL ANNUAL TOTAL RETURN ¹

Best Calendar Qtr.      12/99  66.77%

Worst Calendar Qtr.   9/01 (41.44%)

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UTILITIES FUND — INVESTOR CLASS ACTUAL ANNUAL TOTAL RETURN ¹

Best Calendar Qtr.      12/98 16.33%

Worst Calendar Qtr.   9/01 (23.67%)

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