We utilized data from the 2012 Crane Survey in Kampala, Uganda to estimate prevalence of rape among female sex workers (FSWs) and to identify risk factors for and prevalence of client-initiated gender-based violence (GBV) among FSWs. Participants were recruited using respondent-driven sampling. Analyses were weighted using RDSAT-generated individualized weights for each of the five dependent GBV outcomes. Analyses were conducted utilizing SAS 9.3. Among 1,467 FSWs who were interviewed, 82 % (95 % CI: 79-84) experienced client-initiated GBV and 49 % (95 % CI: 47-53) had been raped at least once in their lifetime. GBV risk increased with increasing frequency of client demands for unprotected sex, length of time engaged in sex work, and FSW alcohol consumption. Risk decreased when sex with clients occurred at the FSW's or client's house or a hotel compared to when sex occurred in open spaces. Our findings demonstrate a high prevalence of GBV among FSWs. This research reinforces the urgent need for GBV prevention and response strategies to be integrated into FSW programming and the continuing need for GBV research among key populations.