Opportunistic ocular infections are a common and important complication of the acquired immunodeficiency syndrome. Cytomegalovirus retinitis is by far the most frequent infection, but other viral, bacterial, and parasitic infections of the posterior segment of the eye may be seen. Infections of the anterior segment are less common but may cause visual loss if not treated. Prompt recognition of these diseases is essential because ocular involvement may be an early sign of systemic dissemination.