The influence of diabetes mellitus on the outcome of arterial reconstructions was evaluated. 25.7% of 2,735 patients (average age: 63.7 years), who underwent arterial reconstruction for arterial occlusive disease, suffered from a diabetes mellitus in need of treatment. The sex ratio within the diabetic patients was 2:1 (male:female). Regardless other influencing factors insulin-depending diabetic patients (average age: 64.6 years) were operated in average 1 year earlier than non-diabetics (average age: 65.5 years). No significant differences were found for perioperative complications. Overall, diabetic patients live significantly shorter than non-diabetics (average age: 72.8 vs. 75.8 years). Concerning the survival after the operation a stronger influence can be seen (8.3 vs. 4.4 years). The lower extremity was found to be the main localization for this negative observation on survival of patients (femoro-popliteal: 8.3 vs. 3.5 years; femoro-crural: 7.7 vs. 3.8 years). No statistical significant differences between diabetics and non-diabetics were found concerning patency rates of a reconstruction of the carotid, the aortic or the iliac arteries. There was a slight tendency pointing to a worse patency in diabetics undergoing reconstruction of the femoro-popliteal level (diabetics: 77%/1, 63%/3, 38%/5 years; non-diabetics: 80%/1, 67%/3, 58%/5 years), but this tendency did not reach statistical significance. A similar result was seen in patients with femoro-crural reconstructions (diabetics: 67%/1, 51%/3, 43%/5 years; non-diabetics: 68%/1, 56%/3, 49%/5 years). We were forced to perform a major amputation significantly more often in diabetics than in non-diabetics (13% vs. 7% after 1 year).(ABSTRACT TRUNCATED AT 250 WORDS)