We experienced 26 cases of free internal mammary artery (IMA) grafting for coronary artery bypass (CABG) during past 44 months. There were 3, 6 distal anastomoses per patient and 1.6 distal anastomoses per patient were performed with free IMA. The early mortality rate (within 1 month after surgery) was 3.8%. The surgical complications were 0 in mediastintis requiring operation, 0 in reoperation for bleeding and 1; phrenic nerve paralysis with respiratory dysfunction, the patency rate at 1 month after surgery were 97.2% in free IMA and were 96.1% in in-situ IMA. Conclusion was as followed that the use of free IMA for CABG provided excellent result in early period and we would anticipate to expand the use of IMA.