Nations in the global South have developed hydropower projects at a rapid pace in recent decades, most notably Brazil and China. These projects have longdocumented impacts on social and ecological systems, yet the implications of hydropower for human well-being and health are not fully understood. In this paper, we examine eight Brazilian Amazon communities in the Madeira river basin, near the Jirau and Santo Antônio dams (sample size: 536 households). We evaluate how impacts on community resources, social capital, and the experience of resettlement influence self-rated health in these communities. Results suggest that the dams strained community resources and social capital, which were associated with reductions in self-rated health. In particular, cognitive social capital (i.e., trust) is lower after the dams' construction. The effect of resettlement and compensation is more nuanced and qualified. This work suggests that hydropower projects have broad deleterious impacts on well-being and health of human populations in hosting regions and that better directed efforts are required on the part of dam developers to reduce these negative outcomes. *The authors wish to thank the National Science Foundation, which through grants 1639115 and 2020790 have provided financial support for this research. They also wish to thank their colleagues at the Federal University of Rondonia (UNIR) who provided local support and expert advice that made survey question formulation and its field collection possible. Numerous students from this university served as enumerators and their local knowledge was very important to this work. They also wish to thank postdocs Juliana Laffer, Amanda Silvino, and Jynessa Dutka-Gianelli, who were in charge of the field survey; Carolina Doria, Mariluce Paes, and other faculty at UNIR were always ready to support the work and we are grateful. Finally, Laura Castro-Diaz and Maria Alejandra Garcia provided inmense support on the survey design. The people in the eight communities were patient in answering our numerous questions and we hope the results herein can lead to improved livelihoods in the future. Despite all this, the authors wish to declare that any errors are the sole responsibility of the authors.