Acute retinal necrosis (ARN) is a rapidly progressive and severe retinitis resulting in a poor visual outcome. Infections caused by herpes viruses such as herpes simplex virus (HSV) types 1 and 2 or the varicella zoster virus (VZV) are known to be implicated in the development of ARN. In the present study, an 80-year-old female with ARN was examined. She had been affected with rheumatoid arthritis and had taken methotrexate for over 10 years. Her right eye showed clinical features of ARN, and her left eye showed mild retinitis. The genomic DNA in the aqueous humor and vitreous fluid from her right eye were analyzed by a comprehensive polymerase chain reaction (PCR) assay to screen infectious pathogens including viruses. The Epstein-Barr virus (EBV) was detected from both specimens, but neither HSV or VZV nor cytomegalovirus was detected. She underwent intraocular surgery following systemic corticosteroid and acyclovir applications. However, although the retinitis of her right eye was extinguished, the final visual outcome was blindness due to optic nerve atrophy. There are few reports indicating that EBV is associated with ARN development. The present findings suggest that EBV alone can be the causative agent of ARN.