The hypertensive lower esophageal sphincter (LES) is defined as one with normal relaxation and an average LES-intragastric pressure gradient greater than or equal to 40 mm Hg. Case histories of two patients with hypertensive LES and normal peristalsis in the body of the esophagus are contrasted to that of a patient with a hypertensive LES and diffuse esophageal spasm. In one patient, the postdeglutitive contractions were excessively prolonged due primarily to a slower return to baseline pressure. It is suggested that the hypertensive LES may be a separate disease entitly, and that it should be separated from diffuse esophageal spasm so that its pathophysiology and natural history can be elucidated.