This paper reports on a choroid plexus hyperplasia in an adult cow suspected of having BSE. The cow was a seven-year-old Belgian Blue with a history of progressive ataxia in the front and hind limbs. No improvement was observed after treatment. On macroscopic examination of the brain, several grayish red masses were found dorsally between the cerebrum and the cerebellum. Histopathology revealed a benign proliferative process of the choroid plexus. This abnormality of the choroid plexus can be added as support for the possible differential diagnosis of bovine spongiform encephalopathy.