Sexually transmitted infections constitute economic burden for developing countries, exposure to causative agents is an occupational hazard for female sex workers. Targeted interventions for this population can reduce the incidence and prevalence of sexually transmitted infections including human immunodeficiency virus, but barriers exists which can hinder effective implementation of such programs. This descriptive cross sectional study sought to assess the prevalence, knowledge and treatment practices of sexually transmitted infections among brothel based female sex workers. Three hundred and twenty three consenting female sex workers were surveyed using pre tested, interviewer administered questionnaires. More than half of the respondents (54.2%) had poor knowledge of symptoms of sexually transmitted infections. Only 13.9% were aware that sexually transmitted infections could be asymptomatic. The self reported prevalence of symptomatic sexually transmitted infections was 36.5%. About half of those with sexually transmitted infectionss sought treatment in a hospital or health centre while 32.5% from a patent medicine vendor. Most respondents (53.8%) mentioned the perceived quality of care as the main reason for seeking treatment in their chosen place. More of the respondents with good knowledge of sexually transmitted infections reported symptoms compared to those with fair and poor knowledge. The knowledge of sexually transmitted infections among these female sex workers is poor and the prevalence is relatively high. Efforts to improve knowledge promote and encourage preventive as well as effective treatment practices must be made for this population.