Diabetes mellitus (DM) imposes a significant burden of early mortality and decreased quality of life on the 6% of Canadians affected by it. There is a growing body of research evidence showing that the use of certain medications (ACE inhibitors, blood pressure medications and cholesterol lowering agents) can reduce the major complications of diabetes such as heart, blood vessel and kidney disease and amputations. Unfortunately this research knowledge does not appear to be routinely translated into clinical practice. The proposed study examines the effect of simple mailed interventions to patients or physicians on improving the use of these therapies. The strategies to be tested are direct patient education with an emphasis on blood pressure and lipid control rather than use of particular drugs and, for physicians, the provision of confidential prescribing feedback together with targeted educational bulletins. With patient and physician consent, health care administrative data will be used to examine the impact of the interventions. If successful, the study will identify low cost reproducible interventions to promote the use of proven preventive therapies in clinical practice.