A complication observed with revisional surgery involving a fistula between the former pouch after gastric banding and the fundus is described. A 59-yearold man with BMI 41 kg/m2 presented for Roux-en-Y gastric bypass (RYGBP). He had previously undergone an open gastric banding operation, with the band removed for obstruction 1 year later. He presented to our hospital with a third incisional hernia which was so large that he suffered from abdominal angina following meals. A RYGBP and a hernia repair with mesh were performed. The postoperative contrast xray study disclosed a fistula between the pouch and fundus. A procedure to close the fistula became necessary. The reason for the fistula may have been an erosion at the former connection between the pouch and the fundus after gastric banding, although a preoperative gastroscopy had not revealed this fistula.