Exploiting a discontinuity in childhood Medicaid eligibility based on date of birth, we find that more years of childhood eligibility are associated with fewer hospitalizations in adulthood. For blacks, we find a 7-15% decrease in hospitalizations and a suggestive 2-5% decrease in emergency department visits, but no similar effect for non-blacks. The effects are pronounced for utilization related to chronic illnesses and for patients living in low-income zip codes. Calculations suggest that lower rates of hospitalizations during one year in adulthood for blacks offset between 2 and 4 percent of the initial costs of expanding Medicaid for all children.