Independently, obstructive sleep apnea (OSA) and infectious mononucleosis are not uncommon in the pediatric population, but acute onset of OSA, as a respiratory complication in the setting of acute EBV infection is extremely uncommon. Previous reports of this clinical entity are sparse and from nearly two decades ago. Urgent adenotonsillectomy was commonly advocated. This complication may be managed medically with systemic corticosteroids and non-invasive continuous positive airway pressure (CPAP), and a case is presented to highlight an updated management approach to this rarely encountered clinical problem in children.