The gastric emptying, expressed as the half-emptying time (T1/2) and mean transit time (MTT90), in 31 obese and 21 control women was studied using a radionuclide technique. No correlation between body weight and body surface area and gastric emptying rates could be found. T1/2 was slightly shorter and MTT90 faster in the obese women than in the controls. There is little chance that a subtle difference in gastric emptying is of any importance in the pathogenesis of obesity.