Objectives: To determine the socio-demographics, sexual practices, and HIV prevalence of male sex workers (MSWs), transwomen sex workers (TSWs), and their male clients in Lima, Peru. Methods –: Following ethnographic mapping of sex work venues, we revisited randomly selected venues to survey MSWs, TSWs and their clients. Results –: MSWs and TSW clients are more educated than MSW clients and TSWs. Only 50% of TSW clients have received HIV testing. Self-reported HIV positivity is highest among MSW clients and TSWs. Conclusion –: Notable differences exist between MSWs and TSWs and their clients that can affect the health of these groups and warrant intervention.