Author studied the value of the plain abdominal films in deciding the operability in 188 infant cases of intussusception by analizing plain films of the abdomen taken routinely before the barium enema applied, who visited Busan National University Hospital during 8 years from January, 1966 to January, 1974. The results obtained were summarized as follows: 1. The 72.4% of the patients observed was below one year of age and male and female ratio was 2.6:1. 2. The 143 cases (76%) of 188 cases were applied barium reduction and then 78 cases (54.5%) had good results. 3. Among the patients who visited the hospital within 24 hrs. after the onset of symptoms the 70 cases (61%) of 114 cases had good results. 4. The 38 cases (75%) of 51 cases who showed normal gas pattern or slight distended gaseous bowel loops and mild air fluid levels on the plain films of abdomen, had good results by barium reduction. 5. The plain films of abdomen showed the marked distension of gaseous bowel loops a d air-fluid levels in the cases arrived at the hospital after 7 hours following the onset of symtoms. 6. The percentage of the success of barium reduction was rather poor in the cases with the mass shadow on the plain films of abdomen than in the cases without it.