 Specific Aim: To assess the efficacy of internet- and referral card-based partner notification tools for the improvement of partner notification outcomes among MSM in Lima, Peru. As attitudes and behaviors related to partner notification vary within specific behavioral, social, and clinical contexts, interventions designed to improve partner notification outcomes must address the same contextual determinants to be effective. Partner notification tools based on electronic distribution of anonymous notification messages andor patient-delivered referral cards are expected to increase notification rates in specific contexts. 