A 43-year-old man, who received total gastrectomy five years ago for advanced gastric cancer, underwent a screening colonoscopy and abdominal CT scan. Abdominal CT scan revealed no abnormal findings. Colonoscopy revealed polyps at the rectum, which were removed by polypectomy. The patient did not complain of abdominal pain or discomfort throughout the procedure. But, he developed right upper quadrant abdominal pain on the next day after colonoscopy. Abdominal CT scan revealed the distended gallbladder with mild wall thickening and suspicious sandy stones or sludge in the gallbladder. The patient underwent an open cholecystectomy. Pathology was compatible with acute cholecystitis. We should be aware of and consider cholecystitis in the differential diagnosis for patients with abdominal pain after colonoscopy.