Study objective Adolescents are at risk for developing a variety of sexually transmitted infections for many reasons. Many of these adolescents present to the emergency department (ED) for their care. We describe the management of adolescent sexually transmitted infections in US EDs. Methods Data were obtained from the 1992 to 1998 National Hospital Ambulatory Medical Care Survey. All visits by adolescents aged 12 to 19 years were identified by any International Classification of Diseases, Ninth Revision code related to sexually transmitted infections. Treatment was reviewed and compared with existing guidelines from the US Centers for Disease Control and Prevention (CDC). Multivariate logistic regression was used to determine the independent association of each of the following variables on antibiotic prescribing rates: sex, race and ethnicity, hospital location, age, and insurance. Results Eighteen thousand nine hundred ninety-nine records that represented 70,693,603 adolescent visits to US EDs were identified during the 7-year study period, of which 351 records representing 1.2 million visits were for a sexually transmitted infection. Mean age was 17.1 years, and 92% were female patients. Overall, 80% of patients diagnosed with a sexually transmitted infection were treated (received antibiotics or were admitted to the hospital); 91% of patients had pelvic inflammatory disease and 71% of patients had other sexually transmitted infections. Eight percent of patients diagnosed with pelvic inflammatory disease were admitted to the hospital. However, treatment for female patients with pelvic inflammatory disease was fully compliant with CDC recommendations in only 35% of cases (95% confidence interval [CI] 19% to 45%) and partially compliant in another 45%; 20% (95% CI 12% to 31%) of patients received either no treatment or treatment not in accordance with guidelines. Male patients were more likely to be treated for sexually transmitted infection (adjusted odds ratio [OR] 6.3; 95% CI 1.0 to 38.7), and Hispanic patients were less likely (adjusted OR 0.3; 95% CI 0.1 to 0.9) to be treated. Age, insurance type, and hospital location were not a factor in receiving antibiotics. For female patients who had a sexually transmitted infection, only 43% had a pregnancy test done, and of all adolescents diagnosed with a sexually transmitted infection, only 1 (0.3%) had an HIV test performed. Conclusion Significant numbers of adolescents sought care for sexually transmitted infections in US EDs. Evaluation and treatment of these adolescents is not optimal. Male patients are more likely to be treated for a sexually transmitted infection. Hispanic patients are less likely to be treated for a sexually transmitted infection. Pelvic inflammatory disease is not always treated with antibiotics, and few patients with pelvic inflammatory disease are admitted to the hospital. HIV testing was almost never done. Further study is necessary to explain these disparities and optimize care.