Fibrosing colonopathy, a complication of cystic fibrosis, has generally been reported in young children with exposure to high doses of pancreatic enzymes. The authors report the case of a 25-year-old male with cystic fibrosis who presented with gradually progressive symptoms of bowel obstruction. Pathologic examination of the right colon revealed findings consistent with fibrosing colonopathy. This case is distinctive because of the adult presentation, and because the patient's symptoms developed long after he had discontinued taking a high-strength enzyme preparation. This case suggests that multiple etiologic factors, and not simply exposure to pancreatic enzymes, may result in fibrosing colonopathy in adults with cystic fibrosis.