Reports that gas reduction of ileocolic intussusception has a better success rate than traditional barium reduction prompted us to evaluate this technique and to compare the results with our previous experience with barium. Our method of intussusception reduction uses oxygen at a flow rate of 2 l/min and with a maximum pressure of 80 mm Hg. The results of 65 consecutive patients with 69 episodes of intussusception over a 9-month period were retrospectively reviewed. For eight episodes, gas enema was not used, including six patients who had barium reduction during the introduction of the gas technique and two patients in whom no intussusception was seen during gas enema were excluded. In the remaining 61 episodes, six patients were considered to be unacceptable risks for attempted therapeutic reduction with either oxygen or barium, according to our current criteria, and had primary surgery. Enemas with oxygen were attempted in 55 cases and were successful in 40 (73%). If all 61 cases with confirmed intussusception are included, the overall success rate with oxygen was 66%. We had greater success with oxygen than with barium (73% vs 53%), although identical pressures were used and the number of severely ill patients referred for therapeutic enema (90% vs 60%) had increased. The change in the referral pattern reflects the adoption of less conservative criteria for excluding patients from having therapeutic enema. No complications have occurred to date. We have had greater success with the use of oxygen than with that of barium, and have had no complications. Therefore, at our institution, oxygen has superseded barium for the therapeutic reduction of ileocolic intussusception.