Nine cases of gastric fistula occurring in patients with Crohn's disease were treated at The Mount Sinai Hospital over the past three decades. Six cases were found in a review of 1480 patients with Crohn's disease admitted between 1960 and 1983. Three others seen at this institution outside the time frame of the author's study have also been included. Among six new cases, five with cologastric fistula occurred among 907 patients with Crohn's disease involving the colon (0.6 percent), while only one with ileogastric fistula was encountered among 1211 patients with ileal disease (0.08 percent). Fistulas between the stomach and colon always originated in an area of colitis, usually passing from distal transverse colon to greater curvature, but occasionally from midtransverse colon to antrum. The only pathognomonic clinical features were feculent vomiting, eructations, or odor. Diagnosis usually was made by barium enema or, less frequently, by upper gastrointestinal series; rarely, the gastric fistula was found unexpectedly at surgery. The conventional and recommended therapy is colectomy with wedge excision of the stomach. Medical treatment with 6-mercaptopurine has been completely successful in one patient and intermittently successful in a second patient.