Analyzing a variety of cross-national and sub-national data, we argue that high adult mortality reduces economic growth by shortening time horizons. Higher adult mortality is associated with increased levels of risky behavior, higher fertility, and lower investment in physical and human capital. Furthermore, the feedback effect from economic prosperity to better health care implies that mortality could be the source of a poverty trap. In our regressions, adult mortality explains almost all of Africa's growth tragedy. Our analysis also underscores grim forecasts of the long-run economic costs of the ongoing AIDS epidemic.