The hypertensive lower esophageal sphincter (LES) (mean LES pressure >45 mm Hg; LES relaxation >75%; normal peristalsis) is a poorly characterized motility disorder associated with chest pain and dysphagia. Therefore, we carried out a multidisciplinary study to assess esophageal pressures and function in 15 symptomatic hypertensive LES patients (3 men, 12 women; mean age, 53 years). On-line computer analysis showed a significant (p < 0.05) increase in LES pressure (55.5 versus 14.9 mm Hg) and residual pressure (6.8 versus 1.1 mm Hg) as well as a decrease in percentage of LES relaxation (87 versus 93%) in patients compared with age-matched controls. All patients had normal peristalsis but 7 of 15 had nutcracker esophagus (mean distal amplitude, 216 mm Hg). No patient had evidence of impaired liquid transport on barium esophagram. The emptying of solids as assessed by radionuclide scans was normal in 14 of 15 patients. Of the 12 patients who completed both psychological inventories, nine had elevated scores on scales assessing anxiety and somatization. The heterogenous nature of this disorder is illustrated by a patient with a changeable narrowing in the distal esophagus associated with the transient impaction of a marshmallow. Dysphagia but not chest pain improved after pneumatic dilatation. We conclude that the hypertensive LES is a heterogenous disorder. Despite abnormal LES parameters, most patients have normal esophageal function, and frequent psychological abnormalities may contribute to their report of symptoms. A minority have abnormal esophageal transit. © 1989 Raven Press Ltd., New York.