We report a case of a 66-year-old man who presented with an abnormal sensation, tenderness, and pain in the middle of his chest in May 2006, two years after a mitral valve replacement for severe mitral regurgitation and a MAZE operation for chronic atrial fibrillation elective cardiac. He was immediately admitted, and the x-ray examination revealed an abnormal elongation of the xiphoid process. At the time of discharge after the initial operation in 2004, x-rays indicated that the length of the xiphoid process was 3 cm; however, in 2006 it had elongated to 6 cm and was prominent in the anterior view. The patient underwent surgical extirpation of the xiphoid process while he was under local anesthesia. Histological examination of the resected xiphoid process revealed no signs of neoplastic or maligant change. The cause of the elongation of the xiphoid process was believed to be distraction tissue neogenesis. The xiphoid process, which fractured and separated from the sternum at the initial operation, was pulled down inferiorly by the rectus abdominis muscles, following which the xiphoid process became elongated and reconnected with the sternum. In cases of a fractured or amputated xiphoid process after median sternotomy, the xiphoid process should be resected to avoid its neogenesis.