Our objective was to assess whether antibiotic prophylaxis should be offered to women post sexual assault by considering acceptability of prophylaxis, follow up attendance rates and the prevalence of sexually transmitted infections (STIs) in these women. Retrospective case notes review of female survivors of rape or sexual assault attending the Rose Clinic, Ambrose King Centre, Royal London Hospital between 1 January 1997 and 31 May 1999 was carried out. The following selection criteria were applied: age greater than 16 years; attending within two weeks of assault; having experienced vaginal and/or anal penetration. All women were screened for STI using standard investigation methods detailed below. Antibiotic prophylaxis was offered within two weeks of the assault, the antibiotic regimens used as recommended. The women were invited to attend for results at two weeks and offered a further screen at three months post assault. Bacterial vaginosis was present in 32% of the women screened, Chlamydia trachomatis was identified in 8%, none tested positive for Neisseria gonorrhoeae. Of the 25 women who were offered antibiotic prophylaxis, 88% accepted. Follow up attendances were 57% at two weeks and 30% at three months. Antibiotic prophylaxis was acceptable to women. Among recent rape victims, follow-up rates are low confirmed by our study. These factors support the use of antibiotic prophylaxis post sexual assault. There was an apparently high prevalence of STIs amongst women in this study. More research is required with respect to this aspect of the work and to consider the cost–benefit analysis of antibiotic prophylaxis.