We report a 75 years old man who was admitted to the hospital with symptoms of severe hypoglycemia. He had a history of a solitary fibrous tumor diagnosed by pathology after its complete surgical resection eight years before. The laboratory examination reported hypoglycemia with inhibited insulin secretion. A computed tomography of the thorax revealed a large solid heterogeneous mass in the left hemithorax. Solitary fibrous tumor is a rare neoplasm. The association of solitary fibrous tumor and paraneoplastic hypoglycemia is known as Doege-Potter syndrome and occurs in less than 5% of all solitary fibrous tumors.We report a 75 years old man who was admitted to the hospital with symptoms of severe hypoglycemia. He had a history of a solitary fibrous tumor diagnosed by pathology after its complete surgical resection eight years before. The laboratory examination reported hypoglycemia with inhibited insulin secretion. A computed tomography of the thorax revealed a large solid heterogeneous mass in the left hemithorax. Solitary fibrous tumor is a rare neoplasm. The association of solitary fibrous tumor and paraneoplastic hypoglycemia is known as Doege-Potter syndrome and occurs in less than 5% of all solitary fibrous tumors.