Gastric emptying was studied in 11 patients who had undergone gastroplasty for morbid obesity 6 to 8 months previously and in 22 normal controls without gastrointestinal disease. A dual isotope technique for measuring solid and liquid emptying was used. Liquid emptying was slower in patients than controls. The emptying of solid was initially faster, but was followed by a prolonged slow rate of emptying indicating retention of solid food in the proximal partitioned pouch. There was no correlation between the weight loss produced by the operation and rates of solid or liquid emptying. Unlike gastric bypass, the changes in gastric emptying produced by gastroplasty were relatively small and gastric emptying rates in patients overlapped considerably with the range of emptying rates found in control subjects. The success of the procedure may depend on the induction of satiety by the filling of the partitioned pouch.