The Diabetes Education Study was a controlled trial of the effects of physician and patient education. This article describes an educational program for internal medicine residents and its effects on ambulatory diabetes management practices. Forty-five of 86 residents practicing in the general medicine clinic of a university-affiliated city/county hospital were assigned randomly to receive a multifaceted program intended to 1) provide specific care recommendations, 2) teach necessary skills, and 3) make the professional and institutional environment more supportive. During the subsequent 11 months, 323 diabetic patients were interviewed and their records audited for evidence of changes in care. Experimental residents utilized fasting blood glucose determinations more often than controls (i.e., during 40% of visits vs. 31%, p = 0.004). Experimental residents also engaged more frequently in a variety of recommended dietary management recommendations. Isolated differences in monitoring/management of chronic complications also were found (e.g., lipid screening: 70% of experimental residents' patients vs. 58%, p = 0.016). Intensive, multifaceted programs of this nature are concluded to result in improvements in diabetes care, over and above that which is attainable through routine methods of clinical training for residents.