The interrelationship between gastroesophageal reflux and Zenker's diverticulum remains unclear. The view that cervical diverticula are induced by gastroesophageal reflux disease (GER) is apparently supported by epidemiologic observations indicating that they occur only in populations with a high incidence of GER. However, it is difficult to prove causality on the basis of currently available physiological and pathophysiological investigations. The few data published to date now end to support a cryptogenic change in upper esophageal sphincter (UES) muscle motility characteristics instead of a reflux induced lesion to the UES. Clinical experience also shows that GER does not play a major role in individual cases of Zenker's diverticula, nor do many surgeons consider it a risk following cervical myotomy. This is confirmed by a very low complication rate even in large series of patients in whom no attempt was made preoperatively to rule out concomitant reflux disease. In conclusion, some facts suggest that reflux disease may be a cause of the development of Zenker's diverticulum. In the majority of cases, however, autochtonic structural lesions to the UES muscle fibers or other, as yet unknown, reasons are more probable.