Due to long term patency, the internal mammary artery is considered as a conduit of choice for revascularization of the left anterior descending coronary artery. The internal mammary artery and its accessory branches in addition to perfusing the chest wall structures also contributes to supplying, part of the female breast arteries. In addition, due to the accompaniment of thoracic duct branches with the left internal mammary artery, harvesting may be associated with injury to these branches and contribute to chylothorax. We report a rare case of chylothorax and the breast necrosis following the coronary artery bypass grafting. The chylothorax was started in the second postoperative day and ceased gradually in the 12th day of operation. The breast necrosis appeared in the 3th weeks of operation with pain, and tenderness and black skin color change. The patient underwent total mastectomy in the 4th weeks of operation.