To develop the 1993 Sexually Transmitted Diseases Treatment Guidelines, experts from the Centers for Disease Control and Prevention reviewed the literature on sexually transmitted disease treatment, assembled tables of evidence, and listed key questions on therapeutic outcome: microbiologic cure, alleviation of symptoms, and prevention of sequelae and transmission. At a meeting with external experts, evidence was systematically assessed and guidelines developed. Quality of evidence for microbiologic cure was generally good for gonorrhea and chlamydia, poor for syphilis, and fair for most other diseases. Evidence on preventing sequelae and transmission was limited. The Guidelines include new recommendations for single-dose oral therapy of gonorrhea (cefixime, ciprofloxacin, and ofloxacin), chlamydia (azithromycin), and chancroid (azithromycin); outpatient therapy of pelvic inflammatory disease (ofloxacin and either clindamycin or metronidazole); and patient-applied therapy of genital warts (podofilox). Syphilis therapy did not change substantially. Several global issues that emerged during the development of the World Health Organization Recommendations for the Management of Sexually Transmitted Diseases also are discussed. This evidence-based approach clarified important treatment issues and the rationale for recommendations, and identified research priorities.