Context: More and more Chinese adolescents are engaging in premarital sexual activity. As a result, the numbers of unplanned pregnancies and sexually transmitted infections (STIs) among Chinese young adults have increased markedly. Methods: A comprehensive sex education program, inc luding information on abstinence, contraception and healthy sexual behaviors, was carried out in a suburb of Shonghai. The program used six methods for providing information and services to unmarried 15-24-year-olds over a period of 20 months. Sexual behavior surveys were conducted among intervention participants and among controls in a comparable town, who did not receive a similar intervention; chisquare tests and logistic regression were used to compare the results. Results: Participation in the interve ntion was not associated with delayed sexual initiation, but was associated with reduced odds that youth coerced a partner into having sex (odds ratio, 0.3) and with increased odds of contraceptive use (6.2) and condom use (13.3) during the intervention period. The greater the level of participation, the larger the protective effects. Furthermore, the proportion of youth reporting pregnancy involvement during the intervention period was significantly lower in the intervention group than among controls (19% vs. 26%). Conclusion: Comprehensive, community-based interventions may be effective in reaching large numbers of Chinese outh and in promoting sexual negotiation, contraceptive use, and pregnancy and STI/HIV prevention.