I investigate the causal relationship between access to health care and criminal behavior following state decisions to expand Medicaid coverage after the Affordable Care Act. Many of the newly eligible individuals for Medicaid-provided health insurance are adults at high risk for crime. I leverage variation in insurance eligibility generated by state decisions to expand Medicaid and differential pre-treatment uninsured rates at the county-level. My findings indicate that the Medicaid expansions have resulted in significant decreases in annual crime by 3.2 percent. This estimate is driven by significant decreases in both reported property and violent crime. A within-state heterogeneity analysis suggests that crime impacts are more pronounced in counties with higher pre-reform uninsured levels. The estimated decrease in reported crime amounts to an annual cost savings of $470 million in each state that expanded coverage.