A 2008 review in the Annual Review of Public Health considered the question of whether health insurance improves health. The answer was a cautious yes because few studies provided convincing causal evidence. We revisit this question by focusing on a single outcome: mortality. Because of multiple high-quality studies published since 2008, which exploit new sources of quasi-experimental variation as well as new empirical approaches to evaluating older data, our answer is more definitive. Studies using different data sources and research designs provide credible evidence that health insurance coverage reduces mortality. The effects, which tend to be strongest for adults in middle age or older and for children, are generally evident shortly after coverage gains and grow over time. The evidence now unequivocally supports the conclusion that health insurance improves health.