This report examines the impact of acquired immunodeficiency syndrome (AIDS) on patterns of mortality among persons aged 15 to 64 years in New York City. The New York City AIDS surveillance registry was matched to the New York City vital statistics registry to identify deaths caused by AIDS. In 1984, the AIDS mortality rate per 100,000 persons aged 15 to 64 years was 42.2 for males and 5.3 for females. Analyzed by five-year age groups, AIDS was among the five leading causes of death for males aged 25 to 54 years, and the leading cause of death for males aged 30 to 39 years. For females, AIDS was the fourth leading cause of death for women aged 25 to 29 years, and the second leading cause for women aged 30 to 34 years. Almost 10% of the years of potential life lost to males aged 15 to 64 years was due to AIDS, and for females, 3.6%. For both men and women in the highest-risk age group, 20 to 44 years, blacks and Hispanics had higher mortality rates than Asians or whites. The higher mortality in blacks and Hispanics is believed to be related to a higher prevalence of drug abuse in these populations and not to ethnicity per se. These findings document the enormous increases in premature mortality attributable to AIDS.