Twelve relatives of a 15-year-old girl with idiopathic intestinal pseudoobstruction were studied with esophageal manometry or cine-esophagography to determine whether the disease was genetically transmitted. Four maternal relatives, including the patient's mother, 13-year-old brother, one aunt, and one of that aunt's children had mild dysphagia and esophageal motor dysfunction. In addition, the patient's mother and 13-year-old brother had a flaccid bladder and bilateral ureteral reflux, respectively. The brother had abnormal bladder smooth muscle by light microscopy. We conclude that idiopathic intestinal pseudoobstruction in this family is secondary to a generalized disease of smooth muscle which is transmitted as a dominant trait of variable expressivity, manifested in some family members as a mild disorder of esophageal smooth muscle dysfunction, at times accompanied by bladder dysfunction. We suggest that this form of idiopathic intestinal pseudoobstruction be called "hereditary hollow visceral myopathy." Esophageal manometry may prove useful as a tool for studying the inheritance of this disorder.