Abstract: Objective To study the prevalence and predictors of human immunodeficiency virus(HIV),syphilis and herpes simplex type 2 virus(HSV-2) infections among MSM in Beijing.Methods The MSM were recruited with convenience sampling and investigated with a face-to-face questionnaire interview in Beijing ctiy betw een August to December,2009.Blood samples were collected to test HIV,syphilis,and HSV-2 infections.Results A total of 962 eligible MSM completed the inteview and blood sampling.The prevalence of HIV,syphilis,and HSV-2 infection was 6.34% (61/962),9.88% (95/962),and 5.30%(51/962),respectively.Multivariate logistic regression analyses showed that HIV infection was associated with non-Beijing residence,having more than 3 sex partners in the latest 6 months,and recent syphilis infection.The syphilis imfection was associated with having the education level lower than college,with HIV infection,and posititve for HSV-2.The HSV-2 infection was associated with at age of more than 25 years,with lower education than college,having more than 3 sex partners in the latest 6 months,having unprotected sex in the past six month,and recent syphilis infection.Conclusion The MSM in Beijing had high infection rates of HIV,syphilis,and HSV-2 and effective education and behavior intervention should be conducted.