Fundoplication performed for gastroesophageal reflux disease may be complicated by postoperative dysphagia despite successful reduction in reflux symptoms. This is more likely in those patients with reflux who have concurrent esophageal dysmotility. The aim of this study was to establish whether esophageal transit studies using a technetium-99m jello bolus (jello esophageal transit) could detect the presence of motility disorders preoperatively and hence predict surgical outcome. Transit studies in 33 healthy volunteers yielded a normal range of 2 to 24 seconds using ninety-fifth percentile distribution. In the second phase of the study, 26 patients accepted for laparoscopic fundoplication were enrolled: jello esophageal transit, manometry, and endoscopy were attempted preoperatively in all subjects. A clinical dysphagia score was assigned from a questionnaire. Six months after surgery, five patients had dysphagia and of these four were found to have abnormal preoperative jello esophageal transit, for a sensitivity of 80%. Of the 21 patients who had no dysphagia after surgery, 20 patients had normal preoperative jello esophageal transit, showing a specificity of 95%. This esophageal transit study is noninvasive, reliable, and sensitive. When performed prior to fundoplication, it appears to be of significant value in detecting a subtle functional motility disorder that predisposes to postoperative dysphagia. Jello esophageal transit may assist the surgeon in planning treatment of gastroesophageal reflux disease.