An analysis of 1819 cases of acquired immunodeficiency syndrome (AIDS) in women reported between 1981 and 1986 showed that the majority of women with AIDS were intravenous drug users. The second most common risk group was heterosexual contact with a person at risk for AIDS. The proportion of women with AIDS in this risk group increased significantly between 1982 and 1986, from 12% to 26%. This trend may prove to be a good marker for following trends in heterosexual transmission. Since the majority of childhood AIDS cases are a result of perinatal transmission from the mother, trends in AIDS cases in women may also predict future trends for AIDS in children.