Large bowel obstruction secondary to colonic gallstone impaction is rare. We report an elderly patient who presented with colonic obstruction secondary to impaction of a gallstone in a diverticular segment of his sigmoid colon. He had severe comorbidities that precluded surgery, and it was not possible to remove the gallstone using standard endoscopic techniques. Endoscopic electrohydraulic lithotripsy (EHL) was performed to fracture the gallstone, and fragments were successfully removed. For comorbid patients who are not fit for general anesthesia, endoscopic stone retrieval should be considered. When faced with large or impacted stones, EHL can be utilized to fracture the stone.