Adolescents are especially vulnerable to acquiring sexually transmitted infections (STIs). Recent national surveillance data and data from population-level studies demonstrate a high prevalence of bacterial and viral STIs in adolescents and striking racial/ethnic disparities. The long-term health consequences of these infections impact heavily on women's reproductive health. Intriguing findings are emerging, suggesting that individual behaviors contribute minimally to risk for STI, and demonstrating the importance of sexual networks for the transmission of STIs. Exciting developments in gonorrhea and chlamydia testing are making routine screening easier for the busy clinician and are acceptable to adolescents. New testing modalities are being used to screen adolescents in nontraditional venues. Recent developments in vaccination against human papillomavirus and new cytological screening recommendations are changing clinical approaches to STI prevention.