Neuropathologic examination of the brain of a 67-year-old woman with a 5-month history of progressive multiple neurologic deficits showed granulomatous angiitis of the small parenchymal and leptomeningeal blood vessels of the brain and spinal cord. Electron microscopy of formalin-fixed brain disclosed intranuclear viruslike particles resembling herpesvirus. Although definitive proof cannot be established without further virologic tests, this previously unreported finding suggests that some cases of granulomatous angiitis of the central nervous system may result from viral infection.