Serious cytomegalovirus (CMV) infection occurs frequently in immunocompromised patients and is a common cause of death. Although primary infection in immunocompetent hosts is normally subclinical, mononucleosis-like syndrome that is characterized by malaise, protracted fever, mild liver function abnormalities, and lymphocytosis with atypical lymphocytes occurs in -10% of patients. Rarely fulminant infection may develop. In both the United States and the United Kingdom, ganciclovir and foscarnet are recommended for the treatment of serious CMV infections in immunocompromised patients. In contrast, there are no recommendations for treatment of severe CMV disease in immunocompetent patients. We describe a case of 45-year-old woman with CMV pneumonia with a fatal outcome for whom there was no evidence of prior immunodeficiency.