Gastric and oesophageal emptying were evaluated in 31 obese patients and 31 control subjects. A double-isotope technique was used to measure gastric emptying of a mixed solid/liquid meal, and oesophageal emptying was measured as the time taken for a bolus of the solid meal to enter the stomach. Gastric emptying of the solid (p less than 0.001) and the liquid (p less than 0.02) meal and oesophageal emptying (p less than 0.001) were delayed in the obese patients compared with the control subjects. There were no significant relationships among gastric emptying, oesophageal emptying, and upper gastrointestinal symptoms in the obese patients alone, but in the total group of 62 subjects there were significant correlations between body mass index and both gastric (r = 0.44, p less than 0.01) and oesophageal (r = 0.45, p less than 0.001) emptying. These results indicate that delayed gastric and oesophageal emptying occurs frequently in obesity and that these abnormalities relate to body weight.