Women attending an inner-city prenatal clinic between February, 1987 and August, 1988 completed a questionnaire to assess risk factors for human immunodeficiency virus (HIV) infection. Women with risk factors were offered HIV testing. Testing was available to women without risk factors upon their request. Stored sera were obtained for anonymous HIV testing on patients not consenting for testing. Overall, 30 of 622 women (5%) tested HIV positive. Ten per cent of women acknowledging risk factors were seropositive vs 3% denying risk factors (P less than .001). Intravenous (IV) drug use was reported in 40% of seropositive women. However, 47% (14/30) of HIV seropositive women denied risk factors for infection. Limiting prenatal HIV screening to women acknowledging risk factors may fail to identify a substantial number of infected women. Screening for HIV infection, counseling, and education on risk reduction should be offered to all pregnant women.