Prevalence of sexually transmitted diseases (STD) and selected behavioral and demographic variables were evaluated in 279 women attending a Baltimore STD clinic, using a standardized questionnaire and cultures for Neisseria gonorrhoeae, Ckla-mydia trachomatis, and Trichomonas vaginalis. Stratified by reason for clinic visit, 102 (37%) of 279 women attending the clinic stated that they were recent contacts to men with STDs with the majority (59 out of 102. or 58%) reporting gonorrhea contact as their reason for visit. Another 124 women (44%) came to the clinic for symptom evaluation, and 53 (19%) for other reasons. Prevalence of STDs was higher among those attending as contacts than among noncontacts: 35% versus 15% for -V. gonorrhoeae; 26% versus 16% for C. trachomatis; and 27% versus 15% for T. vaginalis (P < 0.05 for each). Furthermore, multiple infections were found in 23% of those attending as contacts but only in 10% of noncontacts (P < 0.001). In general, patients reporting contact with an infected person were also less likely to report symptoms (43% versus 34%. P < 0.001). despite increased disease prevalence. These data suggest that multiple STDs are often present in women attending STD clinics, irrespective of reason for visit. Merely treating women for reported exposure without further evaluation will fail to identify a substantial number of women coinfected with other organisms. © 1992 American Sexually Transmitted Diseases Association.