OBJECTIVE To compare the frequency of thrombolytic therapy in diabetic and nondiabetic patients with acute myocardial infarction (MI) and to examine why some diabetic patients do not receive thrombolytic therapy. METHODS Retrospective study of all diabetic patients with acute MI admitted to the coronary care unit of Aalborg Hospital within a 3-year period. RESULTS Only 35% (43 of 123) of patients with diabetes compared with 47% (404 of 856) of patients without diabetes received thrombolytic therapy (P < 0.002). There was no difference in the percentage of patients thrombolyzed among patients admitted to the hospital within 12 h after onset of symptoms. Of diabetic patients who were not thrombolyzed, 60% (48 of 80) arrived at the hospital later than 12 h after onset of symptoms. Among patients who arrived late, 63% (35 of 56) had Q wave infarction and 84% (47 of 56) had symptoms typical of acute MI. Mortality was 29% (16 of 56) in this group. Only one patient did not receive thrombolytic therapy due to diabetic retinopathy. CONCLUSIONS Significantly fewer diabetic patients received thrombolytic therapy compared with patients without diabetes. The main reason diabetic patients did not receive thrombolytic therapy was late arrival to the hospital.