A 3-year-old female ferret died five days after admission to a veterinary clinic for treatment of acute dyspnea and posterior paresis. Blood chemistry showed no hypergammaglobulinemia. Histopathological examination revealed mild to severe inflammatory infiltrates, composed mostly of plasma cells, in multiple organs. Lesions were especially severe in the kidneys, where focal segmental membranous glomerulopathy was also present. In the liver, in addition to lymphocytic and plasmacytic infiltration in periportal areas, dilatation and proliferation of the bile ducts were seen. On analysis of PCR products, using primers directed against the gene encoding Aleutian disease (AD) viral capsid and formalin-fixed kidney samples, we detected a single band of about 400 bp, specific to the AD virus.