In the era of HIV treatment as prevention (TasP), efforts are needed to identify evidence-based combination prevention approaches that achieve greater decreases HIV viral load among populations that are more likely to engage in HIV transmission risk behavior. Because methamphetamine-using men who have sex with men (MSM) are at greater risk for acquiring and transmitting medication-resistant strains of HIV, interventions targeting stimulant use in this population of high-risk men could boost the effectiveness of TasP. At present, only conditional cash transfer approaches such as contingency management (CM) have demonstrated short- term efficacy in reducing stimulant use among substance-using MSM who are not actively seeking formal treatment. The proposed RCT will examine the efficacy of a positive affect intervention that is designed to optimize the effectiveness of CM to achieve long-term reductions in stimulant use and HIV viral load in this population. Our team will examine the efficacy of this integrative intervention in a randomized controlled trial (RCT) with 230 HIV-positive, methamphetamine-using MSM. After enrolling in CM, participants will be randomized to receive either: 1) the positive affect intervention; or 2) a attention-matched control condition. Follow-up data will be collected at 2, 3, 6, and 12 months post-randomization. This RCT will provide an opportunity to examine the efficacy of an integrative intervention designed to promote long-term reductions in HIV viral load as the primary outcome. Secondary outcomes that will be examined include: increases positive affect, reductions in stimulant use, improvements in T-helper (CD4+) count, and decreases HIV transmission risk behavior. Identifying an efficacious intervention approach to decrease HIV viral load among methamphetamine-using MSM would substantially support the goals of the National HIV/AIDS Strategy to reduce HIV incidence and mitigate HIV-related health disparities.