Periodic counseling, testing, and treatment for rectal sexually transmitted infections (STIs) provides a multi- dimensional platform to integrate behavioral and biological HIV prevention strategies for men who have sex with men (MSM) in Peru. Rectal STIs like gonorrhea and chlamydia are key risk factors for HIV acquisition among MSM, both as indirect behavioral markers of recent unprotected receptive anal intercourse (URAI), and as inflammatory factors that increase cellular risk for HIV co-transmission. However, there have been no prospective studies of interventions addressing the specific behavioral and biological risk factors associated with rectal STI transmission or the potential impact on HIV transmission risk of integrating rectal GC/CT screening with other prevention services. We will use nucleic acid testing to screen 750 behaviorally high-risk MSM for rectal gonorrheal and/or chlamydial (GC/CT) infection. GC/CT-positive subjects will receive single- dose antibiotic treatment and either single-session Personal Cognitive Counseling (PCC) (n=50) or standard post-test counseling (n=50). A GC/CT-negative control group (n=50) will also be enrolled to compare biological outcomes including changes in levels of inflammatory cytokines following rectal STI. Aim 1: To adapt a Personalized Cognitive Counseling (PCC) model for use with MSM in Peru. Aim 2: To adapt and pre-test the SJEI and behavioral assessment instruments for use with MSM in Peru. Aim 3: To pilot a combined HIV prevention intervention based on rectal STI counseling, testing, and treatment for MSM in Peru. Estimates of feasibility/acceptability of the intervention, GC/CT prevalence/re-infection rate and the effect onbehavioral and biological mediators of HIV infection will be used to plan an R01 evaluation of rectal STI surveillance as HIV prevention for MSM in Peru.