Background and Objectives: The sexually transmitted diseases (STD) control program for female sex workers (FSW) in Lima, Peru, provided periodic serological tests for syphilis and cervical smears for gonococci, but not medication for STD or condoms. Goal of this Study: to assess program effectiveness. Study Design: We assessed prevalence of current STD and pathogens FWS in relation to program participation and to condom use. Results: Program participation was not associated with significantly reduced rates of current gonococcal or chlamdial infections or Venereal Disease Research Laboratory antibody absorption (FTA-ABS). However, regardless of control program participation, consistent condom use was associated with reduced prevalence of gonorrhea, and with significantly reduced seroreactivity for FTA-ABS, C. trachomatis, anti-hepatitis B core (HBc), and anti-human T-lymphotropic virus type I. Anti-HBc was associated with years of receiving penicilin injection for syphilis prophylaxix. Conclusion: The scope, quality, and efficacy of STD control program must be technically appropriate, well managed, and adequately financed. The safety of marginal programs warrants scrutiny.