A 46-year-old woman who had undergone a barium study for gastric cancer screening the day before presented with abdominal pain. Abdominal radiography and computed tomography revealed a large amount of residual barium, but there was no evidence of ascites or free air. Emergency lower gastrointestinal endoscopy of the sigmoid colon showed an incarcerated barium mass. Emergency surgery was performed for increasing abdominal pain and concerns of perforation. One perforation with a size of 3 cm was found in the sigmoid colon. Hartmann operation and drainage were performed. Postoperative drainage was performed for a hematoma infection around the site of colostomy. Postoperative recovery and progress were satisfactory. Most patients with colorectal perforations have some underlying colorectal disease such as a diverticulum or tumor, and there are few cases arising solely from barium retention. We report a case of colorectal perforation after barium gastrography.