Sixty-four necropsies of patients with multiple myeloma were reviewed to determine (1) frequency of overt manifestations of liver diseases; (2) alterations in tests of liver function; and (3) the spectrum of hepatic histopathologic abnormalities. Hepatomegaly was present in 58% of cases and splenomegaly in 25%. Nine patients were jaundiced with bilirubin values ranging between 3.2 and 17.3 mg/100 ml. Nine patients had exudative ascites, including six without associated peritoneal disease. Increased sulfobromophthalein retention, hypoalbuminemia, and hypoprothrombinemia were frequently present. Plasma cell infiltration of the liver occurred in 40% of cases, usually as either tumor-forming nodules or diffuse sinusoidal infiltration. The data obtained indicate that abnormalities in tests of liver function and extensive plasma cell infiltration of the liver are common findings in multiple myeloma, and that jaundice and exudative ascites occur with surprising frequency in this disorder.