The hypertensive lower esophageal sphincter is an infrequent primary esophageal motor disorder characterized by elevated mean lower esophageal sphincter pressure (greater than or equal to 3 SD from that of controls), sphincter relaxations greater than 75%, and normal peristaltic activity in the esophageal body. This disorder is frequently associated with the nutcracker esophagus. We report our clinical and manometric experience with the isolated hypertensive lower esophageal sphincter (i.e., unassociated with other motor disorders), which constituted 2.7% of all patients who complained of dysphagia or chest pain referred for manometry during the period from October 1982 to February 1991.