PIP: 80 female prostitutes and 120 male clients of female prostitutes attending a sexually transmitted disease (STD) clinic in a red light area of central Mumbai, India, were screened for the prevalence of infection with HIV and 4 other STDs. 84 (42%) subjects were seropositive for both HIV-1 and HIV-2, 144 (72%) for HSV II, 158 (79%) for CMV, 76 (38%) for syphilis, and 52 (26%) for gonorrhea. The highest seroprevalences for all of the STDs, except HIV, were observed in the 26-35 year old age group for both men and women. The highest incidences of HIV were among men aged 26-35 (41.6%) and women aged 16-25 years (55.5%). There was a significantly higher incidence of viral STDs than of bacterial STDs. The association of HIV infection with the 4 STDs is described. A higher incidence of STDs, including HIV, was observed in association with ulcers and genital warts. Demographic characteristics and HIV risk factors for men and women are presented. Viral isolations found a positive percentage of 19.00 and 14.00 for HSV II and CMV, respectively.