The usefulness of the free inferior epigastric artery (IEA) as a coronary bypass graft was studied. Among 149 patients for coronary bypass grafting (CABG) between October 1992 and December 1994, the free IEA was used in 12 patients. The mean number of distal anastomosis was 3.7 per patient. The mean distal size of the IEA was 1.3 mm in diameter and the mean length was 9.4 cm. The IEA graft was anastomosed to the obtuse marginal branch in 5, to the diagonal branch in 4, and the right ventricular branch in 3. The proximal anastomosis of the IEA was constructed to the ascending aorta in three and to the saphenous vein (SVG) or to the internal thoracic artery (ITA) in 4 or 5, respectively. Postoperative angiogram demonstrated patent graft in ten and occluded graft in two in whom the size of IEA was less than 1.0 mm in distal diameter and the IEA was anastomosed to the aorta or to the SVG. The IEA was considered to be useful alternative arterial graft when it was used as "interposed graft" of which proximal anastomosis was made to the ITA and size-matching of the graft to the coronary artery was appropriate. The long-term patency of the graft can determine the true efficacy of the IEA for CABG.