Dysphagia and esophageal motor dysfunction in gastroesophageal reflux are corrected by fundoplication. Abnormalities in esophageal peristaltic function and acid clearance appear to be responsible for prolonged esophageal acid exposure, a major determinant of the reflux esophagitis and esophageal stricture. We evaluated esophageal motility by manometry in 50 healthy controls and in 35 symptomatic reflux patients before, within 6 months, and 1 year after Nissen fundoplication. Preoperative motility was analyzed in relation to the presence or absence of both nonobstructive dysphagia and erosive esophagitis. We found that (a) preoperative dysphagia was related more to peristaltic dysfunction than to esophagitis; (b) peristaltic wave amplitude and duration were significantly lower than control values in patients with reflux, without correlation to degree of esophagitis or lower esophageal sphincter hypotension; (c) dysphagia ceased in most patients after antireflux surgery at the same time that normal motility was restored independently of lower esophageal sphincter pressure increments. These results suggest that motility disturbances are an important cause of dysphagia in reflux disease, and that reflux is the cause of, rather than the consequence of, peristaltic dysfunction. 