Although Medicaid is the largest public payer of behavioral health services, information on access and utilization of services is lacking, and no data on the frequency of service use or types of services provided for children with autism spectrum disorders (ASDs) are available. As states move toward managed care approaches for their Medicaid program, services information is critical. Behavioral health service data for children with autism spectrum disorders were collected from a state Medicaid Managed Care (MMC) program and analyzed from fiscal years 1995 through 2000. Findings revealed that the number of children who received services over time increased significantly; however, the rate of service use was only one tenth of what should be expected based on prevalence rates. The mean number of service days provided per child decreased significantly, about 40%, and the most prevalent forms of treatment changed. Day treatment vanished and medication and case management increased disproportionately to the number of children served. Explanations and implications of the findings are presented as well as recommendations for future research.