BACKGROUND: During June 1981 to June 1982, 37% of more than 400 cases of AIDS reported to the CDC were in minority races and ethnicities. In 2003, 72% of the estimated 43,171 cases of AIDS diagnosed in the 50 states; District of Columbia; and U.S. dependencies, possessions and free nations were in minority races and ethnicities. METHODS: We analyzed HIV/AIDS data for 2000-2003 reported by the 32 states that have had confidential name-based reporting of HIV infection since 1999. For analysis of AIDS data, we used data for 1999-2003 reported by the 50 states and the District of Columbia. HIV/AIDS and AIDS data were statistically adjusted for reporting delays and redistribution of cases initially reported without risk factors. RESULTS: For all years, the numbers of HIV/AIDS and AIDS diagnoses were consistently higher among non-Hispanic blacks than among other races and ethnicities. In the 32 states with HIV reporting, the HIV/AIDS diagnosis rate in 2003 was 74 per 100,000 for blacks, 25 per 100,000 for Hispanics, 11 per 100,000 for American Indians/Alaska Natives, nine per 100,000 for whites, and seven per 100,000 for Asians/Pacific Islanders. The rates for persons living with HIV/AIDS at the end of 2003 were highest for blacks (765 per 100,000) and Hispanics (220 per 100,000). In the 50 states and the District of Columbia, AIDS diagnosis rates in 2003 were 58 per 100,000 for blacks, 20 per 100,000 for Hispanics, eight per 100,000 for American Indians/Alaska Natives, and four per 100,000 for Asians/Pacific Islanders. CONCLUSION: HIV/AIDS disproportionately affects minority races and ethnicities in the United States. To reduce rates of HIV/AIDS in these populations, effective and culturally appropriate prevention interventions must be developed and implemented.