Cytomegalovirus (CMV) retinitis is the most common ocular opportunistic infection in patients with AIDS. CMV retinitis is often asymptomatic and usually appears when the patient's CD4 lymphocyte levels fall below 50/mm3. The infection may present a variety of clinical appearances and must be carefully differentiated from cotton-wool spots in early infection.This paper reviews the natural history of CMV infection in both the normal population and in patients with AIDS. CMV retinitis presenting in AIDS patients is then described in detail with clinical presentations of fundus features. Finally, the management of patients who may be at risk or have developed CMV retinitis is reviewed. Recent data on suggested management protocols are also provided.Cases of CMV retinitis will continue to increase as the AIDS epidemic progresses. The primary care practitioner will play an increasingly important role in the diagnosis and management of patients with this infection.