Introduction Diabetes mellitus is a major cause of coronary artery disease (CAD). Despite improvement in the management of patients with stable CAD, diabetes remains a major cause of increased morbidity and mortality. There is no conclusive evidence that either modality is better than medical therapy alone for the treatment of stable multivessel CAD in patients with diabetes in a very long-term follow-up. Our aim was to compare 3 therapeutic strategies for stable multivessel CAD in a diabetic population and non-diabetic population. Methods It was compared medical therapy (MT), percutaneous coronary intervention (PCI), and coronary artery bypass graft (CABG) in 232 diabetic patients and 379 nondiabetic patients with multivessel CAD. Endpoints evaluated were overall and cardiac mortality. Results Patients (n = 611) were randomized to CABG (n = 203), PCI (n = 205), or MT (n = 203). In a 10-year follow-up, more deaths occurred among patients with diabetes than among patients without diabetes ( P = .001) for overall mortality. In this follow-up, 10-year mortality rates were 32.3% and 23.2% for diabetics and non-diabetics respectively ( P = .024). Regarding cardiac mortality, 10-year cardiac mortality rates were 19.4% and 12.7% respectively ( P = .031).Considering only diabetic patients and stratifying this population by treatment option, we found mortality rates of 31.3% for PCI, 27.5% for CABG and 37.5% for MT ( P = .015 for CABG vs MT) and cardiac mortality rates of 18.8%, 12.5% and 26.1% respectively ( P = .005 for CABG vs MT). Conclusions/interpretation Among patients with stable multivessel CAD and preserved left ventricular ejection fraction, the 3 therapeutic regimens had high rates of overall and cardiac-related deaths among diabetic compared with non-diabetic patients. Moreover, better outcomes were observed in diabetic patients undergoing CABG compared to MT in relation to overall and cardiac mortality in a 10-year follow-up.