This thesis consists of three papers on the economics of female sex work in Bangladesh. Sex workers have been identified as one of the high risk groups in the transmission of sexually transmitted infections (STIs) and human immunodeficiency virus (HIV). In Bangladesh, additional risk factors such as female sex workers (FSWs) regularly entering India to sell sex puts Bangladesh at risk of a HIV epidemic. It is, therefore, important to understand the drivers that motivate FSWs to engage in unprotected sex, while highlighting to them the importance of safe sex practices in order to reduce the transmission of STIs/HIV in Bangladesh.