A 29-year-old man with acquired immune deficiency syndrome (AIDS) was found to have a retinochoroiditis and optic neuritis of his left eye. Results of fundus examination showed inflammatory and hemorrhagic retinal lesions consistent with retinitis due to cytomegalovirus infection. A computed tomographic (CT) scan demonstrated enlargement of the optic nerve. The eye was enucleated and results of histopathologic examination showed retinal necrosis with underlying choroiditis and an optic neuritis. Numerous encysted Toxoplasma gondii organisms were present in the retina and tachyzoites were present in the optic nerve. To the authors' knowledge this is the second histologically documented case of Toxoplasma optic neuritis in a patient with AIDS.