Objectives. To determine if access to medical services differed by regions and to demonstrate the extent of the differences of adopting a claims-based risk-adjustment system versus a demographic model for regional resource allocation. Methods. The claims of a 1% random sample of Taiwan’s National Health Insurance enrollees (N = 173 175) in 2002 was used. The number of visits and morbidity-adjusted resource consumption were calculated individually then collapsed regionally. Regional expected resource allocation was compared with actual consumption. Results. After controlling for diagnosis-based health measures, the average numbers of visits were stable across regions. Two models were consistent in showing over- or underutilization; the overall difference between two models in resource allocation was 5.8% at the district level. We observed strong urban overutilization and rural underutilization. Conclusions. Access to medical services is similar across regions. The adoption of a diagnosis-based model over a demographic-adjusted budgeting method would affect resource allocation considerably.