Diabetes mellitus patients after aorto-coronary bypass operation constitute a patient cohort at largely increased risk for secondary coronary events. Antiplatelet agents and antithrombotic agents are applied for secondary prevention. Up to now, secondary prevention has not been addressed specifically in the cohort of diabetic patients after bypass operation. Hence therapeutic recommendations are derived from the global cohort of CAD patients and based on risk assessment rather than on specific data. Since diabetic patients after myocardial infarction are at particularly high risk, combined therapy with clopidogrel and ASS may be considered even with restricted resources in the health system. Oral anticoagulation with coumadin constitutes an effective alternative to dual anti-platelet therapy. Under specific conditions (ventricular aneurysms, EF < 30%, or certain conditions in coronary anatomy) oral anticoagulants should be considered more liberally than currently.