Aganglionosis is a rare form of neuronal intestinal malformation, which includes hypoganglionosis, neuronal intestinal dysplasia A (NID type A), B (NID type B) or combined type. Classic aganglionosis, or Hirschsprung’s disease is a neurogenic form of neonatal bowel obstruction characterized by a congenital absence of ganglionic cells in the submucosal and myenteric plexus, and presents in childhood with symptoms of constipation, colonic obstruction or sepsis due to enterocolitis. However, aganglionosis can be diagnosed first in adult due to short segment Hirschsprung`s disease with mild symptom and maybe also due to acquired process. We experienced a case of adult type aganglionosis assumed to be acquired type without malignancy or other neurological involvement. (Korean J Gastroenterol 2001;37:470-474)