We compared changes in all-causes mortality rates, 1986 versus 1980, among members 25 to 44 years of age of demographically defined groups with high AIDS cumulative incidence to the changes among same-age, same-sex members of groups with low AIDS cumulative incidence. Among nonwhite men ages 25-44 residing in northeastern New Jersey (NJ) counties, AIDS cumulative incidence was 1,409 cases per 100,000; all-causes mortality was 413.8 deaths per 100,000 per year in 1980 and increased 74% to 726.6 deaths per 100,000 per year by 1986. In contrast, among white men ages 25-44 residing in other NJ counties, AIDS cumulative incidence was 75 cases per 100,000; all-causes mortality fell slightly from 192.6 deaths per 100,000 per year in 1980 to 189.2 deaths per 100,000 per year in 1986. Among nonwhite women ages 25-44 residing in northeastern NJ counties, AIDS cumulative incidence was 435 cases per 100,000; all-causes mortality was 162.07 deaths per 100,000 per year in 1980 and increased 70% to 276.3 deaths per 100,000 per year by 1986. Among white women ages 25-44 residing in other NJ counties, AIDS cumulative incidence was 9.1 cases per 100,000; all-causes mortality was 90.5 deaths per 100,000 per year in 1980 and fell slightly to 83.0 deaths per 100,000 per year in 1986. A substantial portion of the increased mortality of the groups with high AIDS cumulative incidence resulted from causes that have not been associated with HIV infection.