This article presents an analysis of fee-for-service Medicaid data for King County, Washington. This analysis was conducted using Department of Social and Health Services billing records for patients of the community health centers of Seattle-King County (14 primary care sites), the Seattle-King County Department of Public Health (9 primary care sites), and Harborview Medical Center (a large tertiary facility with a primary care outpatient clinic associated with the University of Washington) from January through June, 1992. The complete billing records of all patients who utilized any one of the 24 sites were made available. These records were used to review utilization patterns and patient costs. The implications for community health centers regarding Medicaid managed care, health care reform, and population-based management are discussed.