Appreciation of the spectrum of illness caused by cytomegalovirus (CMV) infections has increased markedly during the past 2 decades. The number of immunosuppressed patients also has increased during the same time period, reflecting the central tenet that CMV disease is most severe in this patient population. Fortunately, antiviral therapies with activity against CMV also have been identified during this same time course, and they include ganciclovir, foscarnet, and cidofovir. Although all 3 of these therapies can have significant toxicities associated with them, nonetheless they are employed with relative frequency to treat potentially life-threatening CMV disease. Ganciclovir is the first-line compound used, followed by foscarnet and cidofovir. This article summarizes those CMV infections that require antiviral therapy and outlines therapeutic options for each. Copyright 2002, Elsevier Science (USA). All rights reserved.