Acute intestinal obstruction remains the most serious common cause for surgical emergencies, even though diagnosis may be difficult in the earlier stage. Clinical features of abdominal distension, vomitting, obstipation and frequent abdominal pain prompt the clinician to consult the radiologist, who is faced with difficult task of informing the surgeon whether or not bowel obstruction to be present. Much of the responsibility rests with radiologist, who is relied upon to answer about location and etiology of stenosis as well as presentness of obstruction. The most valuable aid in determining whether or not obstruction present, is abdominal scout films, whose interpretation depends on a knowledge of many variations in distribution and quantity of intestinal gas and fluid levels. However, the clinical signs may be uncertain, while the radiologic features are definite and conversely, the clinical signs may be sever when then the radiologic findings are meagre. Oral barium has bee indicated when the diagnosis is uncertain both clincally and radiologically and when the diagnosis is almost certain but it is impossible to decide whether the obstruction will remit or progress. In order to identify the etiologic factors of the obstruction, barium contrast study would absolutely be applied. On the basis of mechanical intestinal obstruction, a total of 301 cases were randomly sampled in Yonsei University from 1967 to 1977, which were reviewed according to the correlated etilogic factors for the further radiologic evaluations. Intussusception, band adhesion and congenital diseases constituded the major group of causative disorders which were analyzed according to clinical and radiologic findings.