OBJECTIVES: Overuse of antibiotics has been focused for the public health and pharmaceutical expenditure in Korea. National Health Insurance introduced the antibiotics use monitoring program in 2002. This program includes a monitoring the antibiotics prescription rates of medical institutes, a feedback to prescribers, and a report to the public via website. This study aims to evaluate the impact of this program on the antibiotics prescription rates for the acute upper-respiratory infections (URI) in Korea. METHODS: We assessed the antibiotics prescription rates for the acute URI (J00-J06) of individual medical institutes from 2002 to 2008. Data was extracted from NHI outpatient’s claims database and the first quarter data of each year were selected to avoid seasonal variation. To evaluate the effect of program, we assumed the early change of prescription rate during 2002-2003 as a baseline, and compared it with every year variations of the prescription rate for 2004-2008. Generalized Estimation Equation (GEE) model was constructed to investigate the changes in antibiotics prescription.   RESULTS: Data included about 49 million claims from 13,211 clinics (94.5% of all acute URI claims and 70.5% of all clinics in 2008). Prescription rate declined from 72.8% to 55.1% during 2002-2008. The analysis showed that the antibiotics use monitoring program reduced 6.11% of antibiotics prescription rate per clinic annually (OR: 0.62, 95% CI: 0.61, 0.64, p<0.0001). The reduced antibiotics prescription estimate was average 4.5 million a year.    CONCLUSIONS: After monitoring system introduced, the antibiotics prescription rates for acute URI patients have continuously decreased in the clinics.