A 37-year-old male laboratory technician who sustained a cutaneous penetrating wound from a rhesus monkey developed a progressive ascending encephalomyelitis due to culture-proven herpes B virus (Herpesvirus simiae) infection. He died 6 weeks after his injury despite acyclovir and ganciclovir treatment that was initiated after central nervous system symptoms developed. Histopathological examination of the patient's left eye revealed a multifocal necrotizing retinitis associated with a vitritis, optic neuritis, and prominent panuveitis. Herpes-type virus was identified in the involved retina by electron microscopy. Postmortem vitreous cultures taken from both eyes and retinal cultures taken from the right eye were positive for herpes B virus. Herpes B virus produces infection and destruction of retinal tissues similar to other herpesviruses. To our knowledge, this case represents the first histopathologic demonstration of herpes B virus infection in a human eye.