This article's authors estimate relationships between Medicaid expansions and poverty, using the Census Bureau’s supplemental poverty measure (SPM) and a recently developed health-inclusive poverty measure (HIPM). The HIPM modifies the SPM by adding a need for health insurance to the SPM poverty threshold and by adding a family’s health insurance benefits to family resources. Results from logistic regressions that control for sociodemographic characteristics, income, and benefits other than health insurance show that the (adjusted) HIPM poverty rate is 1.7 percentage points (10 percent) lower in expansion than in nonexpansion states, and the HIPM deep poverty rate is 0.9 percentage points (13 percent) lower. Differences in SPM poverty rates are generally small and insignificant. Medicaid expansion is associated with substantial HIPM poverty reductions for children, persons 55–64 years old, blacks, Hispanics, and those who have not completed high school. These populations are particularly vulnerable to proposed rollbacks in Medicaid expansions.