This study was undertaken to assess our experience with the first 50 patients who underwent CABG without cardiopulmonary bypass. In seven patients left internal mammary artery to left anterior descending artery (LIMA-LAD) grafting was performed through a short left anterior thoracotomy. In 43 other patients median sternotomy was used. Primary CABG was performed in 48 patients; there were two reoperations. Eleven patients had unstable angina. Three patients had left ventricular ejection fraction (LVEF) equal to or lower than 25%. One patient had carcinoma of the right lung coexisting with unstable angina and underwent also right lower lobectomy. In each patient the clinical course, 12-lead ECG, transthoracic echocardiography and the serum levels of creatine kinase (CPK), alanine aminotransferase (ALAT), aspartate aminotransferase (AspAT) were assessed. The need for inotropic or intraaortic balloon counterpulsation (IABP) support and blood transfusion was also recorded. There were three deaths, all in the sternotomy group (6%). A patient with systemic lupus erythemetodes (SLE) died of postoperative MI due to graft thrombosis. Another patient who was found to have porcelain aorta and had LIMA-LAD grafting as a rescue procedure died of MI with low cardiac output. The third patient with unstable angina and ejection fraction of 30% developed postoperative MI with ventricular arrhythmia. One patient with LIMA-LAD graft in whom percutaneous translaminal coronary angioplasty (PTCA) had been abandoned because of coronary spasm developed acute myocardial ischaemia 5 h postoperatively. He had a vein graft placed to LAD in cardiopulmonary bypass, his further course was uneventful. Six patients had IABP support. Nine patients needed inotropic support. Ten patients received blood transfusion. Twelve-lead ECG did not show acute ischaemia or MI, apart from the above described cases. Echocardiographic check showed improved IVS contractility in three patients and better apex motion in one case. In the other survivors the echocardiographic findings were the same as before the procedure. ALAT and AspAT serum levels were normal in all the survivors, and the CPK levels did not exceed 200 IU/ml. One patient from the mini-thoracotomy group had recurrent angina 2 months after the procedure. His left internal mammary artery (LIMA) graft was occluded; we replaced it with a vein graft. All 47 survivors remain asymptomatic, with the mean follow-up time of 6 months. Coronary surgery without cardiopulmonary bypass seems a valuable alternative for high-risk patients.