Retrograde irrigation enemas are commonly used in the treatment of chronic constipation especially in the elderly. We report a case of colorectal perforation due to self-administered retrograde water enema. A 55 year-old chronically constipated male patient was admitted to the emergency unit with severe diffuse abdominal pain. He administered rectal enema using a garden hose directly connected to the water two hours before admission, until he felt a sudden sharp abdominal pain. At the operation he was found to have a perforation along the antimesenteric border of distal sigmoid colon extending to the upper rectum. Primary resection and anastomosis with intraoperative colonic lavage was performed. Postoperative course was favorable without any wound infection or intraabdominal sepsis.