Fistula formation after restorative proctocolectomy poses a challenge to the surgeon and sometimes can lead to the excision of the pouch. A 21-year-old female patient developed an ileal J-pouch-sacral fistula with abscess and osteomyelitis of the sacrum, more than three years after the pouch construction for ulcerative colitis. Two months prior to this event, the patient had a single and transient episode of pouchitis. The role of pouchitis in the aetiopathogenesis of the fistula is unclear. To our knowledge, the late development of such a fistula has not been reported previously.