I investigate how changes in fees paid to Medicaid physicians affect take-up among children in low-income families. The existing literature suggests that the low level of Medicaid fee payments to physicians reduces their willingness to see Medicaid patients, thus creating an access-to-care problem for these patients. For the identical service, current Medicaid reimbursement rates are only about 65 percent of those covered by Medicare. Increasing the relative payments of Medicaid would increase its perceived value, as it would provide better access to health care for Medicaid beneficiaries. Using variation in the timing of the changes in Medicaid payment across states, I find that increasing Medicaid generosity is associated with both an increase in take-up and a reduction in uninsured rate. These results provide a partial answer to the puzzling question of why many low-income children who are eligible for Medicaid remain uninsured.