Between April 1981 and July 1983, 30 patients were operated on for morbid obesity with gastric partitioning and a gastrogastrostomy (GP). The patients were checked 3, 6, 9, 12, and 24 months postoperatively. Radiological investigations were performed on the 5th postoperative day and after 2-32 months. All patients lost weight postoperatively, ranging from 14 to 45 kg after 9 months, but thereafter a slight increase in weight was noted. The weight loss was not correlated with radiologically measured stoma size or volume of the upper gastric pouch. Thus, in contrast studies combined with Gastroluft (sodium bicarbonate, tartaric acid, and dimethicone), pouch distention does not yield prognostic information on anticipated weight loss. More reliable methods for measuring stoma and pouch size are needed, but other factors like patient motivation and a careful postoperative follow-up study with dietetic advice are probably more important for a satisfactory outcome.