A 62-year-old man with liver cirrhosis and hypoxemia was admitted to evaluate the etiology of hypoxemia. The patient had noticed exertional dyspnea for three years. Physical examination, laboratory tests, ultrasonography and liver scintigraphy revealed liver cirrhosis. The arterial blood gas test showed hypoxemia (PO2 46.3 mmHg). Chest roentgenogram showed old pulmonary tuberculosis and the pulmonary function test demonstrated decreased FEV 1.0% and %DLco, which did not account for the marked hypoxemia. Contrast echocardiography was performed by injecting hand-agitated saline into the antecubital vein. Three seconds after the right ventricle was opacified, the contrast echoes appeared in the left atrium and then the left ventricle. Pulmonary arteriography revealed no pulmonary arteriovenous fistula. Hemodynamic data showed low pulmonary vascular resistance. Contrast echocardiography by injecting hand-agitated saline from the catheter tip was performed at both pulmonary arteries and the left atrium was opacified by each injection. The hypoxemia was mainly attributed to a intrapulmonary arteriovenous shunt. Although the etiology of hypoxemia in liver cirrhosis seems to be multifactorial, the intrapulmonary arteriovenous shunt is the most important factor. Contrast echocardiography was useful for detecting this shunt.