Medicaid data for California, Georgia, Michigan, and Tennessee were used to analyze changes in fee and non-fee policies on physicians' service provision to children, before and after the enactment of the Omnibus Budget Reconciliation Act of 1989 (OBRA-1989). Only Michigan raised Medicaid preventive fees relative to the private sector. Higher relative fees increased child caseloads of participating physicians and the likelihood of providing preventive care. However, fee policy is less effective in urban poor areas due to residential segregation. Michigan's and Georgia's non-fee policy changes appeared effective in increasing EPSDT participation relative to the other States.