The acute retinal necrosis (ARN) syndrome is a morphologically defined necrotizing retinitis, occuring in apparently otherwise healthy patients. It has been shown that the varicella zoster virus is at least one cause of the ARN syndrome; treatment with acyclovir has proven to be affective for the infectious component of ARN. We report three immunocompromised patients who developed cutaneous herpes zoster and a nerotizing retinitis that was morphologically similar to the ARN syndrome. All three patients responded promptly to treatment with acyclovir, an agent highly effective against varicella zoster and herpes simplex viruses, but ineffective in the treatment of cytomegalovirus. While cytomegalovirus retinitis is more common in immunocompromised patients, these patients may occasionally develop an ARN-like retinitis, presumbly as a result of the varicella zoster virus, which responds to treatment with acyclovir.