In the presented study we have evaluated short-term and long-term results of the multiple aortocoronary bypass surgery in the patients with ischemic heart disease. We have compared the incidence of the preoperative and postoperative complications, short-term and long-term mortality in the group of diabetics in comparison to nondiabetics as well as the entry characteristics of both groups. Among 2518 patients who were treated with aortocoronary bypass surgery there were 773 (30.6%) diabetics. The diabetic patients were significantly elder, we have found more women among them, more frequent presence of hypertension, chronic heart failure and peripheral vascular disease. Contrary in the incidence of the previous myocardial infarction we have not found any significant difference between both groups. The patients with diabetes mellitus had lower ejection fraction of the left ventricle and significantly more extensive coronary artery disease which explains that in this group of patients the number of coronary bypasses was significantly higher. Comparing the incidence of preoperative complications we have not seen any significant difference between the patients with and without diabetes mellitus. Out of the postoperative complications we have noticed significantly more renal failure, infectious complications, low cardiac output syndrome and bleeding disorders in the diabetic patients. The duration of hospitalisation in the intensive care unit was significantly longer in diabetics (55.11 +/- 89.09 hours to 47.84 +/- 65.18 hours in nondiabetics, p < 0.05). 30 days mortality in diabetics was 3.75% and 2.4% in nondiabetics (p < 0.05). This difference was mainly due to the significantly higher incidence of multiorgans failure as a cause of death among diabetics (1.3% in diabetics, 0.5% in nondiabetics, p < 0.05). 89.1% of nondiabetics and 86.9% of diabetics lived 2-6 years after aortocoronary bypass surgery (n.s.). We have found the significantly higher long-term cardiovascular mortality (2-6 years) in diabetics (10.3%) then in nondiabetics (7.6%, p < 0.05).