In a 50-year-old cook, partial motor seizures and signs of dominant hemisphere dysfunction developed after a brief nonspecific febrile illness. Pleocytosis was seen in the cerebrospinal fluid and findings on cerebral angiography and isotope brain scan suggested a subdural collection. Surgical exploration showed only thickening and inflammation of the dura. Cultures of this tissue and of the patient's blood were positive for Vibrio fetus, an organism common in sheep and cattle, but seen rarely in humans. Among the few reported cases of human infection, several have involved the brain and meninges.