ObjectiveTo provide data on incidence of early diagnosis of HIV infections and define prevalence and incidence of asymptomatic sexually transmitted infections (STI) in men who have sex with men (MSM). MethodsWe assessed a prospective cohort study of HIV-uninfected MSM at high risk for HIV infection. Participants were selected through a risk-assessment questionnaire, and they were screened for HIV infection (quarterly) and for other STI (yearly): syphilis, and hepatitis A, B and C (serology); Chlamydia trachomatis and Neisseria gonorrhoeae in penis and rectum; and human papillomavirus in anus and mouth (PCR). ResultsBetween November 2009 and October 2012, a total of 258 HIV-uninfected MSM at high risk for HIV infection were included and followed up for a median of 2 years (interquartile range 1.4, 2.5). Nineteen acute HIV infections were diagnosed (incidence, 3.9 per 100 person-years). Prevalence of STI at baseline was follows: syphilis 8.4% (95% confidence interval (CI) 5.4–12.7); hepatitis C virus (HCV) 2.0% (95% CI 0.7–4.8); C. trachomatis in penis 3.2% (95% CI 1.5–6.5) and in rectum 6.5% (95% CI 3.9–10.5); N. gonorrhoeae in penis 2.0% (95% CI 0.8–5.0) and in rectum 6.1% (95% CI 3.6–10.1); human papillomavirus in anal canal 75.7% (95% CI 68.8–81.5) and in mouth 3.8% (95% CI 1.8–7.7). ConclusionsThe implementation of the Check-Ear Project in a MSM community centre allowed for the identification of early HIV infections and asymptomatic STI among MSM. The high incidence of HIV infections and the high prevalence of STI strongly support the recommendation of periodic screenings among sexually active MSM.