Purpose: To evaluate the efficacy of CT angiography in preoperative evaluation of internal thoracic arteries, subclavian arteries, celiac trunk and iliac arteries of the candidate of coronary artery bypass graft surgery. Methods: Twelve candidates of coronary artery bypass graft surgery were evaluated with CT angiography from just above the carotid bifurcation to the femoral artery with multidetector row CT scanners with scanning parameters of 2.5-3.2mm slice thickness and 1.25-1.6mm reconstruction interval. Contrast enhancement was performed by injecting a total of 150 mL of nonionic contrast material via antecubital veins (n=3) or dorsal vein (n=6) at a rate of 3-4 mL/sec. All nine patients also underwent the coronary angiography through the radial artery (n=5) or the femoral artery (n=4). The accessibility of the internal thoracic arteries, subclavian arteries, celiac truk and iliac arteries on the both examinations are evaluated by grading system from 1 to 5 points (5 means the best accessible image quality). We also compared number of detected significant lesions on both examinations. Result: The overall average accessibility points are 4.38 for CT angiography and 4.15 for conventional angiography. The image qualities are mainly affected by the route of administration of contrast media in the CT angiography and by the route of approach in the conventional angiography during coronary angiography. The average score is up to 4.67 in CT angiography if the vessels along the route of administration of contrast media are excluded and is up to 4.36 in conventional angiography if the contralateral internal thoracic artery and subclavian artery are excluded in the cases of the radial artery approach. Total 10 stenotic segments more than 50% in diameter were detected in CT angiography including 7 iliac stenoses. The 2 iliac artery stenoses and one subclavian artery lesion were not detected in conventional angiography. Conclusion: The CT angiography is effective method in preoperative extra cardiac evaluation of the candidate of coronary artery bypass graft surgery.