An improved method of free internal mammary artery (IMA)-to-ascending aorta anastomosis for coronary bypass is described. We interposed a small patch of vein with a suitable side-branch or branches in connecting the proximal end of a detached IMA or radial artery. Thirty-four free IMA-to-coronary artery bypasses were performed in 25 patients; 16 right IMA, 14 left IMA, and 4 radial arteries were used. Coronary angiographic follow-up studies performed in all patients between two weeks and six months after operation proved that all grafts were patent and showing a larger lumen than is usually seen in undetached IMA grafts. Concomitantly, marked relief of anginal pain was noted in all patients. Our experience with this technique is very encouraging. All patients are being followed to evaluate long-term graft patency.