At The Hospital For Sick Children, the use of air has recently replaced the use of barium in the reduction of intussusceptions. The purpose of this study was to review the results from 200 consecutive patients with intussusceptions, 100 patients treated with barium enema and 100 patients treated with air enema. The groups were similar with regard to sex, average and median ages, and presenting symptoms and signs. Successful reduction was achieved in 75% of episodes of intussusception treated with barium enema and 76% treated with air enema. Failure of either modality showed a high association with the presence of either a lead point or an ileoileal or ileoileocolic intussusception. Among those cases of unsuccessful reduction, operation was performed in all 59 cases; resection in 30 cases, manual reduction in 19, and spontaneous reduction was found in 10. There were three perforations during attempted reduction with barium and two with air. All perforations were treated by resection and primary anastomosis. There were 18 recurrent intussusceptions following barium enema reduction and nine following air enema reduction. Therefore, with the lower absorption of x-rays by air and the relatively inert nature of air (compared with barium in the event of a perforation), we feel that air enema is the treatment of choice in the initial management of intussusception.