The effect of competition on the quality of health care remains a contested issue. Most empirical estimates rely on inference from nonexperimental data. In contrast, this paper exploits a procompetitive policy reform to provide estimates of the impact of competition on hospital outcomes. The English government introduced a policy in 2006 to promote competition between hospitals. Using this policy to implement a difference-in-differences research design, we estimate the impact of the introduction of competition on not only clinical outcomes but also productivity and expenditure. We find that the effect of competition is to save lives without raising costs.