The effects of combined intravenous and intracoronary streptokinase without (Group I, n = 103) or with (Group II, n = 103) immediate coronary angioplasty were evaluated during a long-term (3 year) follow-up of 206 patients with acute transmural myocardial infarction. There were no baseline differences between the groups with regard to gender, age, infarct location, serum creatine kinase levels, time between onset of symptoms and treatment and coronary artery patency rate. Angioplasty was performed with a success rate of 69% and a reocclusion rate of 2%. Elective angioplasty was performed in 22 (21%) of 103 patients in Group I and 9 (9%) of 103 patients in Group II, with a success rate of 86% and 100%, respectively, reflecting the higher incidence of angina pectoris and antianginal therapy in Group I. Coronary bypass surgery was performed in 21 (20%) of 103 patients in Group I and 20 (19%) of 103 patients in Group II; there was one operative death in each group. During follow-up, coronary reocclusion or reinfarction, or both, occurred in 25 (29%) of 87 patients in Group I and in 16 (18%) of 87 patients in Group II with reperfused vessels (p = NS). Heart failure occurred in 40% of the patients in both groups who had increased end-diastolic and end-systolic volumes. The survival rate after 3 years was 78% in Group I and 80% in Group II (p = NS). Thus, long-term follow-up of patients with acute transmural infarction treated with and without immediate angioplasty does not demonstrate any difference with regard to clinical outcome and mortality.