Purpose: The purpose of this study was to evaluate hospital service utilization by the types of hospitals in Type I Medicaid claims frequently cited by elderly beneficiaries. Methods: Three frequently claimed inpatient diseases were selected: cerebral infarction, hypertension and diabetes mellitus. Relevant data were collected for the year 2008 from the computer database of the National Health Insurance Corporation. The data was analyzed using SPSS by descriptive statistics, ANOVA and coefficient of variation. Results: The coefficient of variance of hospitalization per episode was higher than daily hospital expenditure among hospitals for all three diseases. The coefficient of variance of hospitalization per episode was highest for cerebral infarction. The coefficient of variation of hospital expenditure per hospital day was highest for hypertension. Conclusions: Evaluating of the volume and pattern of hospital service utilization and the appropriateness for hospital admission for Type-I Medicaid elderly beneficiaries is important for Medicaid-based case management.