Seventy-six postpubertal women were referred from a municipal hospital emergency room within 60 h of sexual assault for evaluation. Of the 76 victims, 20 (26%) had active Chlamydia trachomatis infection detected by culture (11 subjects), a fourfold serologic titer rise (6), or both (3). The risk of acquiring C. trachomatis infection after sexual assault was 3%-16%. Pelvic inflammatory disease was detected in 8 (11%) of the 76 victims. Bacterial vaginosis was diagnosed in 38 women (50%), at least 8 of whom appeared to have been infected during the assault. Trichomoniasis was found in 17 victims (22%), at least 5 of whom may have acquired the infection at the time of the assault. In view of the high rates of these infections and the poor compliance with follow-up (76% [58/76] kept their appointments), all postpubertal victims of sexual assault should be offered treatment with ceftriaxone, 250 mg intramuscularly, followed by 100 mg of oral doxycycline and 500 mg of oral metronidazole twice daily for 7 days.