A 25-year-old Caucasian man had difficulty swallowing and shortness of breath during an episode of infectious mononucleosis. His tonsils were "kissing" and erythematous but no superimposed infection with a streptococcal organism was identified. His symptoms improved rapidly upon administration of intravenous steroids. This case demonstrates a rare and short-term complication that is well described in young adults with infectious mononucleosis. Physicians should routinely counsel their patients with infectious mononucleosis to be aware of potentially life-threatening airway obstruction in addition to splenic rupture and meningitis.