Dysphonia is a common presenting symptom in cases referred for otolaryngologic evaluation. Similarly, primary care physicians frequently see adolescents or young adults with symptomatic Epstein-Barr virus infection. Some of the patients with active Epstein-Barr virus infection who have severe clinical manifestations of infectious mononucleosis will be referred for otolaryngologic evaluation. Voice abnormalities in these patients, though, are usually limited to altered resonance due to pharyngeal crowding by hyperplastic lymphoid tissue. We describe a patient with infectious mononucleosis who was referred for evaluation of dysphonia and was diagnosed with unilateral tongue and vocal fold paresis. We also discuss the patient's clinical course and review the related literature. Although uncommon, cranial nerve palsies must be considered in the patient with Epstein-Barr virus infection who presents with voice or speech disturbance. Arch Otolaryngol Head Neck Surg. 2000;126:1491-1494