Progressive outer retinal necrosis syndrome is a recently recognized variant of necrotizing herpetic retinopathy, developing in patients with acquired immune deficiency syndrome (AIDS) or other conditions causing immune compromise. We report a case in which the diagnosis of retinal necrosis syndrome was made before the diagnosis of AIDS was confirmed. A 41-year-old man presented with a 1-month history of blurred vision in his left eye. Ophthalmologic examination revealed extensive retinal necrosis with total retinal detachment in his left eye and multifocal deep retinal lesions scattered in the posterior fundus as well as in the peripheral retina in his right eye. The serologic test for human immunodeficiency virus (HIV) was positive. Despite intravenous acyclovir treatment for 1 week, the lesions in the right eye showed rapid progression. High doses of intravitreal ganciclovir were then given in addition to intravenous acyclovir. After combined treatment for 1 month, the lesions became quiescent and the visual acuity improved to 20/30. Although the patient soon developed full-blown AIDS, the vision in his right eye remained undisturbed. Physicians should suspect progressive outer retinal necrosis syndrome in any patient with rapidly progressive necrotizing retinopathy and test the patient for HIV infection. Aggressive combined antiviral agent therapy should be considered to save vision.