Sexually transmitted infection (STI) rates among men having sex with men continue to increase. HIV services may operate independently to genitourinary medicine clinics and the sexual health of HIV-positive patients may be of low priority in the context of medical problems related to HIV. A prospective study of HIV-positive gay men was conducted in a London outpatient clinic over a three-month period. Data were available for 90 men. Forty-five percent had STI screens in the preceding six months. These revealed a high rate of infections; 26 infections diagnosed in 14 men in the study period. Fifty-seven percent of the 90 men in the study had more than one partner in the past three months and approximately one-third had unprotected sexual activity. A significant proportion of men were unaware of recent outbreaks of hepatitis C and lymphogranuloma venereum and of HIV postexposure prophylaxis. We therefore recommend that sexual history-taking, STI screens and health promotion should become a routine feature of HIV outpatient consultations in this group.