The aim of the present study is to demonstrate a new, simple method of facilitating the submucosal dissetion that is the most difficult and time-consuming part of Soave's operation. For rectal submucosal dissection, oxygen under high pressure is insufflated via a needle inserted into the submucosal space at a level just above the peritoneal reflection of the rectum down to the anal canal. The technique has been successfully used in 35 cases of Hirschsprung's disease. A considerable reduction in the operating time and the incidence of iatrogenic mucosal perforations could be achieved. We conclude that the method is time-saving and provides safety during a period of the operation where scrupulous care is needed.