The authors report the morphology and topography of CNS lesions in experimental kuru (third passage) in the rhesus monkey. The main lesions encountered are spongiosis of the neuropile with neuronal vacuolization, moderate astrocytic gliosis, and slight neuronal depopulation. In all cases, lesions predominated in the grey matter of the cerebral hemispheres (cortex, neostriatum). Lesions were minimal in cerebellum and brain stem. The authors compare their results with these observed in human kuru and experimental kuru of other species of Primates (chimpanzee, spider monkey, marmoset, squirrel monkey).