Acute retinal necrosis (ARN) is an uncommon intraocular inflammatory syndrome characterized by severe and diffuse uveitis, retinal vasculitis, and retinal necrosis. It is typically described to occur in immunocompetent patients, but can also be found in immunocompromised subjects. Varicella-zoster virus (VZV), herpes simplex virus (HSV 1 and 2), cytomegalovirus (CMV), and Epstein-Barr virus (EBV) have been implicated in the etiology of ARN. The characteristic features of the disease include iridocyclitis, vitritis, retinal vasculitis, and retinal necrosis. Bilateral involvement occurs in two-thirds of the patients, frequently in the first six weeks, but sometimes months to years later. Retinal detachment occurs in 75% of the cases. The diagnosis of ARN is usually based in clinical features. The use of polymerase chain reaction (PCR) in aqueous humor samples is useful to identify the etiology of the disease. The treatment of ARN includes intravenous acyclovir, corticosteroids and aspirin. To prevent fellow eye involvement, intravenous acyclovir is followed by oral acyclovir for 14 weeks. Alternatives to acyclovir include ganciclovir, foscarnet, famcyclovir, brivudine, and valgancyclovir.