1. The plain abdominal films of 246 cases of intussusception preceding hydrostatic barium enema were analysedin order to reassess the diagnostic reliability of the abdominal plain film examination. Then, these were comparedwith 42 cases in which the diagnosis had been rejected by means of barium enema. 2. It was found that diagnosis ofthe intussusception was possible in 80% of 246 cases on the basis of plain film findings alone. 3. The most commonand reliable findings of intussusception in plain film diagnosis are those of sparse faecoloid bowel content andsparse amount of intestinal gas. 4. The loops of distended small bowel in cecal or ascending colon area andintraabdominal soft tissue mass are considered to be relatively reliable findings. 5. In 42 cases in which thediagnosis had been rejected by means of barium enema, intussusception was excluded in 745 of the cases on thebasis of plain film findings alone.