Aristotle University of Thessaloniki 54642 Thessaloniki, Greece six-year-old boy was brought to the emergency department because of acute speech difficulties. Five days previously, a low-grade fever, sore throat, and malaise had developed. The day before presentation, difficulties in articulation of speech and tongue movements had developed. The findings on neurologic examination were unremarkable except for left-sided hypoglossal-nerve palsy and associated dysarthria. The results of the clinical and laboratory evaluations were consistent with the presence of infectious mononucleosis. Cranial-nerve palsy is a rare complication of acute infectious mononucleosis in childhood.