Intraarterial digital subtraction angiography (DSA) was performed to evaluate graft patency in 45 patients undergoing coronary artery bypass grafting with the use of internal mammary artery (IMA). Fourty-five IMA grafts and 59 saphenous vein grafts were evaluated using a DSA equipment with a pulse mode of 2 frames per second. A 4F catheter was introduced percutaneously into the left brachial artery. Nonionic contrast medium was nonselectively injected into the left subclavian artery for visualization of IMA grafts and also into the aortic root for visualization of vein grafts. No serious complications occurred. Forty-four IMA grafts and 53 vein grafts were patent. The patency rate was 97.8% for IMA grafts, 89.8% for vein grafts, and 93.3% for all grafts. In 11 patients (24%), intercostal or pericardial branches were visualized. Two patients showed a string sign of the IMA. Intraarterial DSA with nonselective injection of contrast medium into the subclavian artery is a new method for evaluation of IMA graft patency with a low risk.