Background : Hypercholesterolemia is a major independent risk factor of coronary heart disease. Practice guidelines for management of hypercholesterolemia had been made in several developed countries. This study was undertaken to assess the effect of practice guideline reminders and flow-sheets to improve the quality of management of hypercholesterolemia. Methods: Practice guideline reminders and flow-sheets based on National Cholesterol Education Program Adult Treatment Panel II guidelines, were placed on the office desks of outpatient department of family medicine at the Asan Medical Center. Before this intervention, we educated the doctors to use these reminders and flow-sheets. The charts of all patients who had cholesterol levels greater than or equal to 240 mg/dl during 4 months before and after introduction of reminders and flow-sheets, were reviewed retrospectively. We compared the performances of physicians about management of hypercholesterolemia between pre-intervention period and post-intervention period. Results: The detection rate of hypercholesterolemia in post-intervention period was increased to 83.2% compared by 71.5% in pre-intervention period. Risk factor analysis for coronary heart disease increased significantly from 16.9% to 68.7%. Adequacy of management was 19.2% in pre-intervention period and 78.0% in post-intervention period. It showed statistically significant improvement in management of hypercholesterolemia. Conclusion : This study suggested that practice guideline reminders and flow-sheets were the effective methods in improving the quality in management of hypercholesterolemia.