The association between neighborhood environment and prevalence of STIs, sexual partner variables and condom use among adolescents with psychological disorders was examined. Cross-sectional data in three urban areas of the US (Southeast, Northeast and Midwest) were obtained from 384 sexually active male and female participants who provided urine samples for laboratory-confirmed testing of Neisseria gonorrhoeae, Chlamydia trachomatis and Trichomonas vaginalis. A total of 15.4% of participants tested positive for one of the three STIs. Results indicated that relative to adolescents living in low risk neighborhood environments, those living in high risk environments were significantly more likely to have a STI and to report having casual partners. Findings suggest that in high risk neighborhoods, STI acquisition may be less dependent on condom use and more dependent on other contextual factors. The importance of expanding public health research to include assessment of neighborhood context as a determinant of sexual risk-taking is emphasized.