Recent data suggest that the prevalence of HIV/syphilis infections among men who have sex with men (MSM) in China increased rapidly. This cohort study was to assess the correlates of the incident infections for HIV, syphilis, and hepatitis B virus (HBV) among sexually active and HIV-negative MSM in China. A cohort of 507 HIV-seronegative MSM was recruited from November 2006 to February 2007. Sociodemographics, sexual and drug use behaviors, uptake of HIV-prevention services, and HIV, syphilis, and HBV seroconversions were assessed at 6- and 12- month follow-up. The incidence rates were 2.6 per 100 person-years for HIV, 16.9 per 100 person-years for syphilis, and 3.3 per 100 person-years for HBV. Multivariate Cox regression analyses showed that syphilis infection (hazard ratio [HR] = 3.6; 95% confidence interval [CI]: 1.1-11.6) and no perceived risk of HIV infection (HR = 6.0; 95% CI: 1.6-22.7) were independently associated with HIV seroconversion. Predictors for syphilis seroconversion included less education (HR = 1.87; 95% CI: 1.1-3.3), found male sex partners through bathhouses/public washrooms/parks (HR = 2.19; 95% CI: 1.2-4.0), drank alcohol 4 or more times monthly (HR = 1.95; 95% CI: 1.1-3.6), and had sexually transmitted diseases (HR = 2.65; 95% CI: 1.5-4.5). The only predictor for incident HBV seroconvension was having more male sex partners in the past 3 months (HR = 11.8; 95% CI: 1.5-90.4). Alarmingly high incidence rates of HIV, syphilis, and HBV were found among MSM concurrently with high prevalent risky behaviors and low uptakes of health care services. The findings of this study underscore the urgent needs for a comprehensive intervention strategy to curtail the rapid spread of HIV, syphilis, and HBV.