A 1-year-old male chinchilla with a 2-week history of conjunctivitis suffered subsequently from neurological signs comprising seizures, disorientation, recumbency and apathy. After 3 weeks of progressive central nervous disease the animal was killed in view of the poor prognosis. A non-suppurative meningitis and polioencephalitis with neuronal necrosis and intranuclear inclusion bodies were observed at necropsy and by light microscopy. The brain stem and cerebral cortices were most severely affected. Both eyes displayed ulcerative keratitis, uveitis, retinitis and retinal degeneration, and optical neuritis. Additionally, a purulent rhinitis with focal erosions, epithelial degeneration and intranuclear inclusion bodies was present. Ultrastructurally, herpes virus particles were detected in neurons of the brain. Immunohistochemistry with antisera specific for human herpes virus types 1 and 2 resulted in viral antigen labeling in neurons, glial cells and in neuronal processes. Viral antigen was found in the rhinencephalon, cerebral cortices, hippocampus, numerous nuclei of the brain stem, single foci in the cerebellum, and in a solitary erosive lesion of the right nasal vestibulum. Viral antigen was not detected in the eyes. The virus was isolated from the CNS, and nucleic acid sequence analysis of the glycoprotein B and the DNA polymerase revealed a sequence homology with human herpes virus type 1 of 99% and 100%, respectively. The clinical signs, the distribution of the lesions and the viral antigen suggest a primary ocular infection with subsequent spread to the CNS. Chinchillas are susceptible to human herpes virus 1 and may play a role as a temporary reservoir for human infections.