Low pressure or inappropriate relaxation of the lower esophageal sphincter, disturbances in esophageal peristalsis and delayed gastric emptying are the most important pathogenetic factors of reflux disease. In general, retrosternal and also epigastric and pharyngeal burning or pain are the leading symptoms, but in mild disease eructation may become the major complaint. Diagnosis is usually made on the basis of a typical history and the results of endoscopy. 24-h-pH-recording is indicated in inconclusive endoscopy, chest pain of unknown origin and preoperative evaluation. Manometry may be indicated to exclude systemic sclerosis.