Chylothorax is a rare complication of coronary artery by-pass grafting. We present two patients who developed a left chylothorax at one week and 14 days post-coronary artery by-pass grafting. In both cases an internal mammary artery graft was harvested. Nonoperative therapy, which included adequate pleural drainage and a low fat diet, lead to successful resolution of the chylous leak in each instance.