Introduction. Gallstone ileus (GSI) of the colon is an extremely rare entity with potentially serious complications including perforation. Case Presentation. An 88-year-old man presented to the emergency department with abdominal pain and distension. Clinical exam revealed signs of peritonism. Computed tomography (CT) revealed GSI of the transverse colon with a closed-loop large bowel obstruction (LBO) and caecal perforation. The patient underwent emergency laparotomy. A right hemicolectomy was performed, the gallstone was removed, and a primary bowel anastomosis was undertaken. A Foley catheter was sutured into the residual gallbladder bed to create a controlled biliary fistula. The patient recovered well postoperatively with no complications. He was discharged home with the Foley catheter in situ. Discussion. Gallstone ileus is a difficult diagnosis both clinically and radiologically with only 50% of cases being diagnosed preoperatively. Most commonly it is associated with impaction at the ileocaecal valve and small bowel obstruction. Gallstone ileus should also be considered as a rare but potential cause of LBO. This is the first reported case of caecal perforation secondary to gallstone ileus of the transverse colon. Successful operative management consisted of a one-stage procedure with right hemicolectomy and formation of a controlled biliary fistula.