Mediastinitis is a devastating complication after cardiac surgery. An omental flap transposition is frequently used for the treatment of poststernotomy mediastinitis. Here we describe a new technique of omental transfer into not only the mediastinum but also the subcutaneous dead space. After an irrigation and débridement of inflammatory tissues, the greater omentum was dissected along with the right gastroepiploic artery and transferred into the pericardial cavity. The omentum was turned over the sternal edge and the anterior aspect of the sternum was covered in order to eliminate the dead space. The patient survived with this technique and postoperative computed tomography (CT) showed developed omental tissue around the sternum. We consider that greater omentum is the ideal reconstruction tissue for deep sternal wound infections. This modification is thought to contribute to the improvement of surgical mortality of this lethal complication.