The Earned Income Tax Credit (EITC) is a central component of the U.S. safety net, benefiting about 27 million families. Using variation in the federal and state EITC, this paper evaluates the long-term impact of EITC exposure during childhood on the health of young adults. We find that an additional $100 in the average annual EITC exposure between ages 0 and 18 increases the likelihood of reporting very good or excellent health by 2.7 percentage points and decreases the likelihood of being obese by 1.0 percentage point between ages 22 and 27. Direct program transfers, increases in pre-tax family earnings, and increases in health insurance coverage are channels through which the EITC improves health.