New tools are needed to bring down ongoing high HIV incidence. This review aims to evaluate the place of one of these new tools (pre-exposure prophylaxis) in a comprehensive prevention strategy. Several trials have demonstrated the safety and the efficacy of pre-exposure prophylaxis in HIV prevention. Two large trials have, however, failed to show such efficacy. This was likely due to poor adherence in these trials. New forms of long-acting pre-exposure prophylaxis currently in trials may deal with these problems of low adherence. Pre-exposure prophylaxis has been demonstrated to be cost-effective within certain settings. The introduction of pre-exposure prophylaxis into prevention programs needs to be carefully thought through. For example, pre-exposure prophylaxis-induced risk compensation, at both an individual and population level, could undermine other aspects of a comprehensive HIV prevention program. In conclusion, pre-exposure prophylaxis could be a useful additional tool for the prevention of HIV in specific high-risk groups. It should be implemented in a way that deals with issues such as ensuring high adherence and ensuring that pre-exposure prophylaxis does not detract from, but complements, other more fundamental elements of HIV prevention programs.