Objectives-To assess the prevalence of sexually transmitted infections (STIs), frequency of sexual risk behaviors, and relationship between knowledge of HIV infection status and sexual risk behavior among HIV-infected men who have sex with men (MSM) attending an STI clinic in Peru.Methods-We recruited a convenience sample of 559 MSM from a municipal STI clinic in Lima, Peru. Participants completed a survey and provided blood for HIV, Syphilis, and HSV-2 antibody testing, and urine for gonorrhea and chlamydia nucleic acid testing.Results-Among 124 HIV-infected MSM, 72.6% were aware of their HIV-infected status. Active syphilis (RPR≥1:8) was diagnosed in 21.0% of HIV-infected participants, HSV-2 in 79.8%, urethral gonorrhea in 1.6%, and chlamydia in 1.6%. Among 41 participants reporting insertive anal intercourse with their last sex partner, 34.2% did not use a condom. Of 86 participants reporting receptive anal intercourse, 25.6% did not use a condom. At least one episode of insertive unprotected anal intercourse (UAI) with an HIV-uninfected partner during the previous six months was reported by 33.6% (35/104) of participants, and receptive UAI with an HIV-uninfected partner by 44.6% Key Statements: Many HIV-infected MSM in Peru engage in sexual practices that carry a high risk of HIV transmission to uninfected partners. In a sample of MSM with previously diagnosed HIV infection, no evidence of serosorting or seropositioning harm reduction strategies was observed. No difference in the prevalence of high-risk sexual behavior was seen when comparing men with newly diagnosed HIV infection from those who were aware of their HIV infection status.