41 year-old male with liver cirrhosis accompanying severe hypoxemia was presented. Shortly after the diagnosis of liver cirrhosis, he suffered from exertional dyspnea and cyanosis. Though home oxygen therapy had been prescribed for 2 years, hypoxemia gradually progressed accompanied by persistent cough, mucous sputa and intermittent fever. The chest X-ray revealed bilateral interstitial shadow particularly localized in lower lung fields. The arteriovenous shunt ratio was shown to be 24% by oxygen method. Perfusion lung scan using 99mTc-labeled MAA revealed perfusion defects in bilateral lung fields and radionuclide uptake was strongly demonstrated in the kidneys. These clinical data suggested that severe hypoxemia was probably due to multiple arteriovenous shunt. With further progression of hypoxemia for 4 months, he died of hepatic failure and pulmonary infection. Autopsy showed Miyake's type B cirrhosis. Multiple pleural and subpleural arteriolar nevi were demonstrated grossly and microscopically. There were no arteriovenous malformations demonstrated after injection of barium-gelatin solution into the pulmonary artery. Histologically, irregularly dilated vessels were found in the lung parenchyma beneath the pleura and filled with blood and injection material. These clinical and pathological findings provided evidence that the mechanism of arterial desaturation was pulmonary arteriovenous shunting due to liver cirrhosis.