Health insurance holds the promise of improving population health and survival and protecting people from catastrophic health spending. Yet evidence from lower- and middle-income countries on the impact of health insurance is limited. We investigated whether insurance expansion reduced adult mortality in rural China, taking advantage of differences across Chinese counties in the timing of the introduction of the New Cooperative Medical Scheme (NCMS). We assembled and analyzed newly collected data on NCMS implementation, linked to data from the Chinese Center for Disease Control and Prevention on cause-specific, age-standardized death rates and variables specific to county-year combinations for seventy-two counties in the period 2004–12. While mortality rates declined among rural residents during this period, we found little evidence that the expansion of health insurance through the NCMS contributed to this decline. However, our relatively large standard errors leave open the possibility that the NCMS had effects on mortality that we could not detect. Moreover, mortality benefits might arise only after many years of accumulated coverage.