A ventricular aneurysm developed after myocardial infarction in a 50-year-old man. It was large enough to cause a bizarre configuration of the heart shadow in chest roentgenograms and was found at thoracotomy to measure 10 cm. in diameter. Extracorporeal circulation, employing a bubble diffusion oxygenator and roller-type complete occlusion pumps, was established by inserting one catheter into the common iliac artery through the right common femoral artery and another catheter, with openings at two levels for the superior and inferior venae cavae, through the right common femoral vein. The adherent parietal pericardium was dissected from the surface of the aneurysm, and the aneurysm was then completely excised, with the edges trimmed back to the fuctioning myocardium of the left ventricle. Closure was made with a continuous suture of silk reinforced with interrupted mattress suture of silk, and the suture line was 10 cm. in length. The patient's early postoperative course was moderately complicated by fever, but after this subsided on the third day his recovery was uneventful. He was dismissed from the hospital in ambulatory condition 18 days after operation. Since this initial report, another patient with a similar lesion underwent operation successfully.