Résumé : Introduction: HIV in sub-Saharan Africa remains a great concern in men who have sex with men (MSM). Intervention on MSM is a key strategy to control the burden of HIV among this population. Herein we assessed the effect of 2 years of HIV testing and counseling on risk-tacking and HIV and STI incidences among MSM living in Bangui in the Central African Republic. Methods: The incidences of HIV, syphilis and hepatitis B and the sexual behavior characteristics were assessed at inclusion and after 2 years of follow up in the prospective MSM cohort. Results: 99 MSM were included and followed up during 2 years. The mean age of study MSM was 24 years (range, 14-39); among those, the majority was single (84.8%) and unemployed (33.3%) or students (23.9%). The majority (up to 80%) were living in only 4 (out of 10) neighboring district of Bangui. Insertive anal intercourse showed significant decrease from 54% at inclusion to 46% after 2 years of follow up (P < 0.001). In contrast, we observed slight increase in receptive anal intercourse (60% versus 66%) and oral sex (70% versus 74%), but the difference did not reach statistical significance. Finally, the prevalences of HIV, syphilis and hepatitis B increased significantly from 29% to 41%, 12% to 21% and 14% to 23%, respectively. Conclusion: These observations indicate that medical care and counseling on MSM does not provide significant changes in risk-taking, whereas the incidences of HIV, syphilis and hepatitis B remained high. Innovative interventions should be conceived for the MSM population living in Bangui.