• Acute cytomegalovirus mononucleosis has been associated with maculopapular rashes, petechiae, purpura, urticaria, ulcerative lesions, and vesicular eruptions. Although erythema nodosum has been reported in association with a number of infectious and noninfectious diseases, to our knowledge it has not been associated with cytomegalovirus infections. We report the first case of an adult patient with acute cytomegalovirus mononucleosis who presented with erythema nodosum. (Arch Intern Med1988;148:323-324)