OBJECTIVES: In light of the transition of the Alabama Medicaid program to a primary care case management model, we assessed the level to which children had access to a medical home before and after implementation of that model. Given the growing emphasis within the MCH community on assuring children medical homes, we explored whether Medicaid claims data could be used to assess medical home coverage. METHODS: We operationally defined "medical home" as use of a single primary care physician combined with receipt of at least one well child visit from that physician during the year. Using Alabama Medicaid claims data we assessed whether children's receipt of health care services met this defintion, the extent to which Medicaid-enrolled children had primary care providers and received well child visits, and changes in the source of well child visits before and after implementation of a primary care case management model in 26 of Alabama's 67 counties. RESULTS: In general, Medicaid-enrolled children in Alabama did not meet our definition of medical home either before or after implementation of a primary care case management model. Only 11.8% of children saw a single provider and had a well child visit from that provider during the baseline year. A majority of children (49.9%) however had both a primary care provider and received a well child visit. Sixteen percent of children saw a primary care physician but received no identifiable well visit, while 11% had well child care but did not see a primary care physician. Of particular concern, 23% neither saw a primary care physician nor had a well child visit during the baseline year. These figures changed only slightly in the 26 counties examined before and after implementation of the primary care case management model. CONCLUSIONS: State Maternal and Child Health programs are required to report as a performance measure "the percent of children with special health care needs in the state who have a medical/health home" as part of their Block Grant application. Using Medicaid data, this simple measurement strategy can provide an indication of the extent to which at least one population of children receive care through a medical home.