Objective:The laryngeal mask airway (LMA) is an established way for airway control during spontaneous ventila-tion. Its ability to deliver positive pressure ventilation without leakage especial y in low flow states is stil controversy. The aim of this study is to test the possibility of using LMA in pediatric closed circuit control ed ventilation, and to find out the optimum cuf volume to perform closed system ventilation. Methods:Twenty children scheduled for elective surgeries were enrol ed in a crossover study. Laryngeal mask airway was used. In stage I, the cuf was inflated with the maximum volume of air as rec-ommended by the manufacturers. Adjustment of volume of air inflated into the LMA cuf to the minimum volume to obtain the ef ective seal was done at stage II. The leak pressure, intracuf pressure and the leak volume were measured in both stages. Results:The cuf fil ing volume was significantly lower compared to the maximum cuf inflation volume in stage I. Leakage values showed significantly less values in stage II of the study with smal er cuf inflation volumes. The airway leakage pressure was significantly lower in stage II in comparison to stage I. Cuf inflation pressure in stage I showed marked elevation which dropped significantly after adjustment of cuf volume in stage II. Conclusion:Laryngeal mask airway is an ef ective tool to provide closed circuit control ed ventilation in pediatrics. Inflation of the cuf by the minimum volume of air needed to reach the just sealing pressure is suggested to minimize the leakage volume.