An improved technique of free internal mammary artery (IMA) to ascending aorta anastomosis for coronary bypass is described. A small patch vein with a suitable side branch or branches is interposed, connecting the proximal end of a detached IMA to the ascending aorta. A single or double free IMA alone or in combination with an additional saphenous vein graft was performed in 77 patients. A total of 125 free IMA grafts were done. The hospital mortality was 2.7% and late mortality 1.4%. Seventy one of the 74 surviving patients had no angina and returned to a normal life. Postoperative coronary arteriography in 65 patients showed a patency rate of 96%. One year's experience with this technique is very encouraging. However, prolonged follow up is necessary to determine if free IMA, as used by us, will increase the long term patency rate.