This study provides the background recommendations of the US Preventive Services Task Force for interventions by primary care physicians to prevent sexually transmitted diseases. Rationale for and data supporting use of barrier methods, epidemiologic treatment, contact tracing, patient education, prophylactic antibiotics, and disease reporting are discussed. Specific recommendations include those for gonorrhea, syphilis, human immunodeficiency virus infection, enteric infections, human papillomavirus infection, herpes simplex virus infection, and Chlamydia trachomatis infection.