Cytomegalovirus (CMV) retinitis in persons with AIDS can be ameliorated but not cured by induction and maintenance therapy with either ganciclovir sodium (Cytovene) or foscarnet sodium (Foscavir). Ganciclovir is preferred as initial therapy by most physicians who treat AIDS and is better for patients who have preexisting renal dysfunction. Foscarnet is the drug of choice for patients with preexisting bone marrow suppression or for those who wish to continue a full dose of zidovudine (Retrovir). Its use has been associated with longer survival in persons with AIDS, and there are data to indicate that it has an anti-HIV effect. If this anti-HIV effect, seen in laboratory studies, is shown to confer clinical benefit, foscarnet my prove to be the drug of choice for the treatment of CMV retinitis in persons with AIDS.