This cross-sectional study identified the prevalence and correlates of condom-use errors among female sex workers (FSWs) in Armenia. One hundred and seventeen street-based FSWs aged 20-52 years completed an interviewer-administered questionnaire. Condom-use errors were reported by 78.0% of participants. Number of clients, higher frequency of condom application on clients by FSWs, greater perceived barriers to condom use, elevated depressive symptomatology and having sex while drinking alcohol were significantly associated with higher number of condom-use errors. History of sexually transmitted infections (STIs) was marginally significant while consistent condom use was not significant in the final model. The multiple regression model accounted for 32.5% of the variance in condom-use errors. Condom-use errors are prevalent in this population, thus attenuating the intended protective effects of condoms. Interventions with FSWs in Armenia should specifically address the factors identified in this study toward the goal of reducing condom errors and ultimately preventing acquisition of STIs including HIV.