Analgesia using a self-administered mixture of 50% nitrous oxide and 50% oxygen (Nitronox) was evaluated prospectively in 22 children undergoing closed reduction of fractures in the emergency room. The majority of these patients underwent reduction of forearm fractures. When the children were asked about pain after the procedures, 12 (60%) recalled no pain, 7 (35%) minimal pain, and 1 (5%) moderate pain. None recalled severe pain. Eleven (52%) of the patients had minimal pain, 8 (38%) had moderate pain, and 2 (10%) had no pain, as judged by an emergency room physician. None had severe pain. There were no complications and the ease of administration was remarkable. We conclude that N2O:O2 in a 50:50 mixture provides very effective, safe analgesia for fracture reduction in the emergency room setting.