['Current Centers for Disease Control (CDC) guidelines recommend that sexually transmitted disease (STD) screening measures for high-risk populations such as homeless youth prioritize testing in out-of-clinic settings and incorporate new approaches to STD eradication, such as field-delivered testing and treatment and patient-delivered partner therapy (PDPT). Our non-medically trained research staff offered field-based STI testing, field-delivered therapy, and PDPT to homeless youth in the context of a longitudinal study.', 'A total of 218 ethnically diverse (34% female) 15-24-year-old homeless youth recruited from street sites in San Francisco completed an audio computer-administered self-interview survey and provided a first-void urine sample for testing for chlamydia (CT) and gonorrhea (GC). Youth testing positive were offered field-delivered therapy and PDPT. A random subset of 157 youth was followed prospectively, of whom 110 (70%) were interviewed and 87 (55%) retested at six months.', 'At baseline, 99% of youth in the study consented to STI testing, of whom 6.9% and .9% tested positive for CT and GC, respectively. Ninety-four percent of positive youth were treated, 50% within one week. The incidence rate for CT was 6.3 per 100 person-years (95% confidence interval [CI]: 1.3-18.4) and for GC was 4.2 per 100 person-years (95% CI: .5-15.2). None of the youth treated by study staff and tested six months later (n = 6) had CT or GC on follow-up testing (95% CI: 0-131.3).'] Are street-based STD testing and treatment of homeless youth feasible , acceptable and effective?