Reoperation for failed gastric bypass procedures for obesity. Reoperation is worthwhile when there is an obvious defect in the gastric reduction operation that has failed to control weight. Reoperation occasionally is necessary to correct a complication of gastric bypass. Vertical banded gastroplasty is the operation of choice for reoperations, as it provides weight control while eliminating the problems of bypass. Conversion of a horizontal to a vertical pouch is safe but requires careful attention to the technique to avoid injury to the other organs in the area and preservation of blood supply to the stomach. The gastrogastrostomy across the old horizontal staple line in the vertical pouch can be constructed in a way that will minimize the risk of obstruction. Vertical banded gastroplasty is now the only operation in use at UIHC for the treatment of obesity and is used not only as the primary operation but in all reoperations. Bypass of the stomach and duodenum is not necessary for weight control and adds some risk of malabsorption and duodenal and stomal ulcer plus a lifetime of inaccessibility of the excluded areas for diagnostic and therapeutic measures. 