In our outpatient department we often see patients with vitreous inflammation. Recent reports emphasize that vitreous inflammation is very rare, so we looked for patients with cytomegalovirus (CMV) retinitis and vitreous inflammation. We investigated 359 HIV-positive patients for at least 1 year; all patients reached the stage of AIDS disease. We included patients without any retinal signs of CMV retinitis at the beginning or CMV recurrence during the study. A slit-lamp investigation, binocular funduscopy and b-picture ultrasound were done at regular intervals. The results show an increase in vitreous inflammation with the frequency of CMV retinitis recurrences. Patients very often develop retinal detachment. Vitreous inflammation is a critical factor when examining CMV retinitis. In the future a larger series of patients should be examined.