We experienced one case of severe pituitary dwarfism in a 16 years old male boy that magnetic resonance image(MRI) revealed transection of the pituitary stalk with the ectopic location of posterior pituitary gland and hypoplastic anterior pituitary gland. The serum growth horrnone(GH) response to clonidine and L-dopa revealed severe GH deficiency. The patient revealed normal response in TSH, prolactin and LH, FSH to TRH and LHRH respectively. So far, the primary cause of idiopathic pituitary dwarfism in many patients was due to hypoxic injury to hypothalmus by perinatal insults. In this patients, there was no history of perinatal insults and postnatal head trauma. We report a case of severe dwarfism due to hypogenesis of anterior pituitary gland(J Kor Soc Endocrinol 11:324-329, 1996).