Functional paraganglioma of the mediastinum is an uncommon tumor of the paraganglion system that causes symptoms and signs of episodic catecholamine release. It has not been reported in Korea. We experienced a case of a 17 years old man with a history of diaphoresis and paroxysmal hypertension refractory to therapy since 14 years old. Urinary execretion of catecholamine and its metabolites were elevated. Computed tomography(CT) scan revealed high density mass located on the posterior mediastinum in the area of the right fifth intercostal space. At thoracotomy, a 3X3X4cm sized lesion was resected and confirmed as a paraganglioma.