The internal mammary artery is considered the elective graft for performing aortocoronary by-pass as its long-term results have proven better than those obtained with the internal saphenous vein. Our results in a series of 21 patients in whom both internal mammary arteries were used are reported. Four patients (19.04%) needed reoperation for sternal dehiscence and two of them had mediastinitis (9.52%). Those patients were successfully treated by continuous povidone-iodine flushing. A clear statistical difference was found between this group of patients, in whom both internal mammary arteries were used, and the rest of the patients (182 patients) in whom just the internal saphenous vein and/or only one internal mammary artery was used. The second group presented 8 cases of sternal dehiscence (4.39%) and 1 mediastinitis (0.55%).