A syndrome characterized by hypoxemia aggravated by exercise, orthodeoxia, hypocapnia, and evidence of hyperdynamic circulation, but otherwise normal indices of pulmonary air flow, volume, and distribution of ventilation has been observed as an infrequent complication of hepatic cirrhosis. An illustrative case is described, the features of which support the presence of a shunt or shunt-like mechanism consisting of low-resistance vascular communications within the lung. We suggest that this may represent the existence of a hepatopulmonary syndrome analogous to the hepatorenal syndrome.