This study analyzes the 4-year phase-in of Medicaid Primary Care Case Management (PCCM) in Georgia and Alabama. The effect of PCCM implementation on children's primary and preventive care, independent of changes in Medicaid participating providers, was measured by race. Accounting for provider supply, PCCM was associated with lower use of primary care for all children except white non-Hispanics in urban Georgia. In urban Alabama, PCCM reduced preventive care for white and black non-Hispanic children. This held only for blacks in urban Georgia, while PCCM was associated with increased preventive care among all children in rural Georgia. The negative effect of PCCM was further compounded by negative effects of reduced provider availability. Reductions in office-based Medicaid providers affected Alabama children more often, while reductions in hospital-based physicians had a negative effect for Georgia children. Implementation of PCCM without fee increases may have had unexpected negative effects that differentially affected minority children. © 2006 Sage Publications.