Objectives: The rate of sexually transmitted diseases (STDs) in China has soared over the past 20 years. There is a need to study STD prevalence in the general population of the country. Goal. To report the prevalence and patterns of STDs and the relationships between STD status and demographic and behavioral factors. Study Design: A total of 4510 market vendors in a city in eastern China were interviewed and tested for STDs. Results: The prevalence of any STD among participants was 16.55% (women, 21.04%; men, 11.54%). Among those who tested positive for an STD, chlamydia was most common (8.89%), followed by herpes (6.50%). Participants who had no schooling and participants who had college or higher level of schooling had a similarly high STD prevalence (26.19% vs. 24.00%, respectively). Prevalence of all STDs was significantly higher among women, those with more discretionary income, and those with multiple partners. Conclusions: Special considerations are needed for low versus high education groups as well as men versus women to maximize the effects of STD prevention programs and messages in China.