Cytomegalovirus (CMV) retinitis is the most common retinal opportunistic infection in AIDS patients and is the main cause of blindness. It is generally associated with a CD4+ lymphocyte count below 50/microL. CMV retinitis is often asymptomatic (54% of the cases), frequent ophtalmoscopic screening is very important. Two virostatic drugs (Cymevan and Foscavir) have been approved for the treatment of CMV retinitis. Both are effective in preventing the progression of the lesion within 3 weeks of induction therapy. Long-term use of virostatic maintenance therapy delays the onset of relapses. The differential diagnosis of CMV retinitis are: human immunodeficiency virus retinopathy, varicella-zoster virus retinitis, ocular toxoplasmosis, syphilis, candida endophthalmitis in intravenous drug users, and unfrequently, tuberculosis, choroidal pneumocystosis, intraocular lymphoma.