Five patients with idiopathic intestinal pseudoobstruction were studied with esophageal manometry and all had abnormalities of esophageal motility. In 2, primary peristalsis was replaced by simultaneous contractions and repetitive spontaneous activity was marked. The lower esophageal sphincter failed to relax and the Mecholyl test was positive in both. In the other 3, primary peristalsis was absent, low amplitude simultaneous waves followed swallows, no spontaneous activity was present, and defects in lower esophageal sphincter relaxation were found in two. The Mecholyl test was negative in the one patient tested. The esophagus appears to be abnormal in idiopathic intestinal pseudoobstruction and could prove useful as an organ for diagnostic study in patients who may have this syndrome.