OBJECTIVE To test how Certificate of Need laws affect all-cause mortality in the United States. DATA SOURCES The data of 1992-2011 all-cause mortality are from the Center for Disease Control's Compressed Mortality File; control variables are from the Current Population Survey, Behavioral Risk Factor Surveillance System, and Area Health Resources File; and data on Certificate of Need laws are from Stratmann and Russ (). STUDY DESIGN Using fixed- and random-effects regressions, I test how the scope of state Certificate of Need laws affects all-cause mortality within US counties. PRINCIPAL FINDINGS Certificate of Need laws have no statistically significant effect on all-cause mortality. Point estimates indicate that if they have any effect, they are more likely to increase mortality than decrease it. CONCLUSIONS Proponents of Certificate of Need laws have claimed that they reduce mortality by concentrating more care into fewer, larger facilities that engage in learning-by-doing. However, I find no evidence that these laws reduce all-cause mortality.