Despite a large decline in new adult HIV infections in eastern and southern Africa from 2005-2015, progress has slowed dramatically in recent years and multiple disparities have persisted within countries and between men and women. Most alarmingly, HIV risk among adolescent girls and young women in the region remains extremely high. Transactional sex, or the exchange of material support or goods in non-commercial sexual relationships that are often age-disparate, is widely believed to be among the main driving factors for the HIV risk in this population. Although various structural and biomedical HIV prevention interventions are have targeted adolescent girls and young women, there is a large gap when it comes to interventions targeting men who engage in transactional sex. The proposed pilot project seeks to fill this important gap by leveraging the rapid expansion of mobile phone ownership and access to financial services in Africa and using behavioral economic principles to promote behavior change among men and address key HIV prevention priorities. The project will assess the acceptability, feasibility, and potential impact of a novel prize-linked savings intervention designed to shift men’s income away from alcohol and transactional sex and towards saving for the future. Prize-linked savings accounts have been in existence for many years in some countries and they offer savers a random, lottery-like payout proportional to the amount participants save, instead of traditional interest income. A number of banks, employers, and policymakers have recently promoted this low-cost, scalable approach to increasing savings among low-income individuals. However, there have been no assessments of whether prize-linked savings interventions can induce changes in key health-related behaviors as well. We will conduct a pilot randomized trial among men in Kenya to assess whether offering prize-linked savings opportunities leads to reduced spending on alcohol and transactional sex. In addition, we will explore whether the intervention leads to reduced financial stress and builds future-orientation among men – all of which could lead to reduced risk-taking behavior. The project will enroll ~100 men who in communities with high HIV risk, randomize them to the savings intervention, and assess changes in key economic and self-reported health outcomes over a 3-month period with baseline and follow-up surveys. Findings from the pilot trial may reveal new ways to influence the HIV epidemic in priority regions where it continues unabated and will directly inform the design of a larger-scale study that focused on ways to achieve changes in health and economic behaviors. Several aspects of this study would fall directly within the HIV prevention priorities laid out by NIH and countries in eastern and southern Africa.