Sexual violence is associated with women's risks for HIV infection. The current study investigated factors related to risks for sexually transmitted infections (STIs), including HIV, among South African women with a history of sexual assault. An anonymous street intercept survey of women (N = 272) living in an African township in the Western Cape, South Africa assessed demographic characteristics, history of sexual assault, HIV risk behaviours, substance use and non-sexual relationship abuse. Surveys were completed by 90% of women approached. Forty-four per cent (N = 119) of women reported a history of sexual assault. Multiple logistic regressions, controlling for participant age, education, marital status and survey venue, showed that women who had been sexually assaulted were significantly more likely to have shared injection drug equipment, exchanged sex to meet survival needs, and used alcohol compared to women who had not been sexually assaulted. Women with a history of sexual assault were also significantly more likely to have multiple male sex partners, greater rates of unprotected vaginal intercourse, lower rates of condom protected anal intercourse, more sexual contacts involving blood, more STIs and genital ulcers. Finally, women who had been sexually assaulted were more likely to have been non-sexually abused by relationship partners and were more likely to fear asking partners to use condoms. There is a close connection between sexual assault and women's risks for STIs and HIV. Structural and behavioural interventions are needed to simultaneously reduce the prevalence of sexual assault against women and prevent the transmission of HIV.