Intraoperative graft flow, measured by a BF 1001 CardioMed Flowmeter and the postoperative graft diameter of the left internal thoracic artery, measured by coronary angiogram were compared in the semi-skeletonization method group (23 patients) and the skeletonization method group (29 patients). There was no significant difference between 2 groups in terms of age, gender, body surface area, diabetes mellitus, LAD lesion, preoperative ejection fraction, operation time, cardiopulmonary bypass time and aortic cross-clamp time. Graft flow was significantly larger in the skeletonization method group than in the semi-skeletonization method group (50.4±21.7ml/min vs 36.9±12.8ml/min, p=0.019). However graft diameter did not differ significantly between the 2 methods (2.46±0.44mm in the skeletonization method group and 2.38±0.42mm in the semi-skeletonization method, p=0.991). These results suggested that left internal thoracic artery could be used longer by either 2 methods than by pedicled harvesting technique, however skeletonization method caused less spasm during graft harvesting than the semi-skeletonization method.