As part of a study on etiology of sexually transmitted infections (STI) among 520 women presenting at the STI clinic in Nairobi, data on partner violence and its correlates were analyzed. Prevalence of lifetime physical violence was 26%, mainly by an intimate partner (74%). HIV seropositive women had an almost twofold increase in lifetime partner violence. Women with more risky sexual behavior such as early sexual debut, number of sex partners, history of condom use and of STI, experienced more partner violence. Parity and miscarriage were associated with a history of lifetime violence. We found an inverse association between schooling and level of violence. Six percent of the women had been raped. Gender-based violence screening and services should be integrated into voluntary counseling and testing programs as well as in reproductive health programs. Multi-sector approaches are needed to change prevailing attitudes towards violence against women.