The liver is a common site of amyloid deposition in primary systemic amyloidosis. We reviewed the clinical features and natural history of patients with primary systemic amyloidosis and biopsy-proven hepatic involvement who were evaluated at Mayo Clinic from January 1, 1975, to December 31, 1997. The median age of the study group (68 men; 30 women) was 58.5 years. Seventy-one patients (72%) had involuntary weight loss. Hepatomegaly was found in 79 patients (81%). Eighty-two patients (89%) had proteinuria, and 81 patients (86%) had elevated serum alkaline phosphatase levels. Seventy-six patients (83%) had either a serum or urine monoclonal protein. Before liver biopsy, clinicians considered amyloidosis in the differential diagnosis for only 14 patients (26%). None of our patients experienced hepatic rupture or death due to liver biopsy, and only 4 (4%) bled after liver biopsy. The median survival of the 98 patients was 8.5 months. Predictors of a poor prognosis were congestive heart failure, elevated concentrations of bilirubin, and a platelet count greater than 500 x 109/L. In conclusion, clinicians should consider the diagnosis of primary hepatic amyloidosis in patients who present with involuntary weight loss or hepatomegaly. Other clues to the diagnosis include an unexplained elevated serum alkaline phosphatase level, proteinuria, and evidence for hyposplenism (for example, Howell-Jolly bodies on peripheral blood smear). Liver biopsy was safe. Some patients benefit from systemic chemotherapy.