The purpose of this study is to evaluate the effectiveness of using a diabetes registry program as part of a comprehensive quality improvement program. Diabetes care management objectives were compared between 82 patients of physicians who participated in the quality improvement program and 63 patients of nonparticipating physicians. Overall completion of management objectives increased 26.1% in the intervention group versus 2.6% in the control group. The intervention was associated with a dramatic improvement in compliance with care management guidelines and is strongly recommended in other community clinic settings.