A massive hepatic infarction was found in a 44‐year‐old man who had suffered from polyarteritis nodosa for two years. The polyarteritis had been well controlled by administration of corticosteroids, but he died due to an opportunistic fungal infection. At autopsy, a massive hepatic infarct and a fresh thrombus occluding the right portal vein trunk were found. In addition, occlusion of the heptic arterial branch with fibrosis and dissociation of elastic fibers due to polyarteritis was noted. Massive hepatic infarction is uncommon. The clinicopathologic features of this case are described, and the pathogenesis of hepatic infarcts is discussed. ACTA PATHOL JPN38: 89–93,