OBJECTIVE: Interventions that mitigate drowning risk in developing countries are needed. This study presents the cost-effectiveness of a low-cost, scalable injury and drowning prevention program called Prevention of Child Injuries through Social-Intervention and Education (PRECISE) in Bangladesh. METHODS: Between 2006 and 2010, the 2 components of PRECISE (Anchal, which sequestered children in crèches [n = 18 596 participants], and SwimSafe, which taught children how to swim [n = 79421 participants]) were implemented in rural Bangladesh. Mortality rates for participants were compared against a matched sample of nonparticipants in a retrospective cohort analysis. Effectiveness was calculated via Cox proportional hazard analysis. Cost-effectiveness was estimated according to World Health Organization–CHOosing Interventions that are Cost Effective guidelines. RESULTS: Anchal costs between $50.74 and $60.50 per child per year. SwimSafe costs $13.46 per child. For Anchal participants, the relative risk of a drowning death was 0.181 (P = .004). The relative risk of all-cause mortality was 0.56 (P = .001). For SwimSafe, the relative risk of a drowning death was 0.072 (P < .0001). The relative risk of all-cause mortality was 0.750 (P = .024). For Anchal, the cost per disability-adjusted life-year (DALY) averted is $812 (95% confidence interval: $589\x{2013}$1777). For SwimSafe, the cost per DALY averted is $85 ($51\x{2013}$561). Combined, the cost per DALY averted is $362 ($232\x{2013}$1364). CONCLUSIONS: Based on World Health Organization criteria, PRECISE is very cost-effective and should be considered for implementation in other areas where drowning is a significant problem.