Crohn's disease is a rare cause of gastrocolic and duodenocolic fistulas. Only 83 examples (27 gastric, 52 duodenal, four both) have been described. Weight loss, abdominal pain, and diarrhea are common features but fail to distinguish a fistula from active inflammatory bowel disease. Fecal vomiting is pathognomic but is present in one third of gastrocolic and only 2% of duodenocolic fistulas. Diagnosis is most readily made by contrast radiography, with barium enema being more sensitive than barium meal. Although several gastrocolic fistulas have been successfully treated with long-term 6-mercaptopurine, surgery is the mainstay of therapy. An isolated duodenocolic fistula should not be regarded as the primary indication for operation because most are asymptomatic. Ileocolonic resection with simple gastric or duodenal repair is safe and effective in most cases. An ileocolonic anastomosis should be positioned away from the stomach or duodenum or protected with omentum to prevent recurrent fistulization. A number of fistulas appear to have arisen from gastric or duodenal Crohn's, but the vast majority originate from diseased colon.