OBJECTIVES: In Korea, prescribing evaluation program is being conducted for some drugs having a high risk of misuse or abuse like antibiotics, injections and expensive drugs. The goal of this policy is to guarantee the adequacy of drug prescription based on medical, pharmaceutical, and cost-effective assessment. This could identify the overall trends of drug prescription for each medical institute as well as comparison among medical institutes. METHODS: It was conducted using prescribing evaluation index developed by HIRA (Health Insurance Review and Assessment Service) using national health insurance claims data. The indexes account for prescribing patterns such as antibiotics prescription rate, injections prescription rate, drug cost per prescription day, the number of drugs per prescription, adrenocortical hormone prescription rate, duplicated prescription rate of NSAIDs (Non-Steroidal Anti-Inflammatory Drugs), and indicators for promoting generic prescription. RESULTS: According to the results of fourth quarter of 2010, antibiotics prescription rate, injections prescription rate and the number of drugs per prescription were higher in primary care clinics than general hospitals. In case of drug cost per prescription day, costs were lowest in primary care clinics and were highest in tertiary hospitals. In case of prescription rate of high price drug, rates also were highest in tertiary hospitals and the degree of reduction was highest in primary care clinics. CONCLUSIONS:   Since this prescribing evaluation program conducted, antibiotics prescription rate with acute upper respiratory infections was dropped by 10%p. By making public the results, it also could induce each medical institute to improve prescribing patterns by themselves. To take a more effective policy, financial incentives for medical institutes and/or education for prescriber are needed in addition to feedback of the results.