From June 1985 to November 1992 eight eastern quolls (Dasyurus viverrinus) and six Tasmanian devils (Sarcophilus harrisii), held at institutions in Australia and Canada, developed progressive blindness and posterior paresis progressing to paralysis. All were aged individuals. At necropsy white matter tracts, particularly in the spinal cord, optic tracts, and cerebellum, contained evidence of severe axon degeneration with vacuolation and macrophage infiltration. The surrounding tissue had evidence of gliosis. The etiology of the condition is unknown but may be a form of age-related degeneration.