Background:New York City has only 3% of the U.S. population but has reported nearly 16% of all AIDS cases.Methods:This is an observational study using the New York City vital events and AIDS case surveillance registries to describe trends in HIV/AIDS mortality from 1983 through June 30, 1998.Results:Annual HIV/AIDS deaths increased steadily until stabilizing at 7046 in 1995, declined 29% to 4998 in 1996, and declined 47% to 2625 in 1997. Comparing data from 1997 with those from 1995, declines occurred in all demographic groups and in all major HIV transmission categories: 74% in men who have sex with men, 68% in injecting drug users, and 64% in heterosexuals. In the first 6 months of 1998, declines were smaller than they had been in previous 6-month intervals in all demographic groups except Hispanic males and those between 35 and 44 years of age. From 1995 to the first 6 months of 1998, the number of people living with AIDS in New York City increased 22% (from 32,692 to 39,976).Conclusions:The precipitous 63% decline in HIV/AIDS deaths from 1995 to 1997 occurred at the same time that more effective antiretroviral therapies became widely available. The slowing in the mortality decline observed in 1998, however, suggests that although these new therapies may have a profound effect at the population level, deaths due to AIDS will continue.