We report a patient with AIDS who developed rapidly progressive, acute outer retinal necrosis. Cytomegalovirus etiology was proposed as a possibility in view of the histopathologic identification of the virus in the fellow concomitantly affected eye. Treatment with ganciclovir resulted in disappearance of the posterior pole lesions and inactivation of the peripheral lesions. We suggest that ganciclovir be used as soon as this condition is suspected in order to optimize the outcome.