We report a case of a diaphragmatic hernia, with perforated viscus, originating from the diaphragmatic incision that was made to accommodate the right gastroepiploic artery coronary artery bypass graft. Avoidance of an excessively large right gastroepiploic artery pedicle and interrupted sutures placed at the limits of the diaphragmatic incision, perpendicular to the direction of the musculotendinous fibers of the diaphragm, should prevent this potentially lethal complication. Prompt recognition and treatment of this complication when it occurs is lifesaving.