The postoperative chest radiographs of 100 consecutive patients undergoing median sternotomy were reviewed for the presence of acute rib fractures. The majority of patients underwent coronary artery bypass grafting. Thirteen patients sustained 15 fractures. Eleven of these fractures were of the left first rib and 7 of the 15 fractures occurred at the costotransverse articulation. The fractures tended to be subtle on the postoperative portable chest radiographs and were initially overlooked in 4 patients. Heavier patients and those with larger body surface areas were more susceptible to the development of fractures. There was no statistical correlation to total operating time, bypass time, or global ischemic time.