This study was performed to evaluate whether coexistent diabetes mellitus has any adverse effect on the outcomes of thrombolytic therapy in patients with acute myocardial infarction. Although the early reperfusion rates were similar between the two groups of patients who had acute myocardial infarction with and without diabetes mellitus (42% vs 45.4%, p > 0.05), the results of late angiographic examination showed a significantly lower rate of patency in infarct-related coronary artery (defined as TIMI 3 flow) in diabetics compared to nondiabetics (28.9% vs 41.3%, p < 0.001). The global left ventricular function was also poorer in diabetics (left ventricular wall motion score was 18.6 +/- 7.3 in diabetics and 14.1 +/- 4.6 in nondiabetics, p < 0.01).