ObjectiveTo investigate the relationship between heterosexual behaviors associated with HIV infection and ethnicity, sex, and intravenous drug use.MethodsSubjects were recruited from Bellevue Hospital Center, New York City between 1986 and 1989, and interviewed about sexual behaviors and intravenous drug use. Analyses were based on 1561 black, white, or Hispanic individuals who reported having sexual contact with a member of the opposite sex.ResultsTwenty-seven per cent of the study population were black, 43% Hispanic, and 31% white. Blacks were more likely than whites or Hispanics to have initiated sexual intercourse at an early age, and to have had a sexually transmitted disease. Sex with a female drug user was more common among white men, and contact with a prostitute more frequent among Hispanic men. Among the women, Hispanics had fewer sexual risk factors overall than whites or blacks. Use of barrier contraceptives was uniformly low across all ethnic groups. Intravenous drug use was significantly associated with sexual risk-taking. Women were more likely than men to have an intravenous drug-using (IVDU) sexual partner.ConclusionsThe large prevalence of high-risk sexual practices observed in this study emphasizes the continuing need to target AIDS prevention programs at those at highest risk of heterosexually transmitted HIV: racial minorities, IVDU, and their sexual partners.