Endotracheal intubation is the most useful and safe method to keep airway in general anesthesia. But there are many problems such as severe cardiovascular changes, difficult intubation, larygospasm and tracheal stenosis in using laryngoscope and tracheal intubation. Laryngeal mask airway(LMA) is new method to keep airway and has many advantages such as easy insertion, decreasing cardiovascular changes, insertion without muscle relaxant, decreasing damage of pharynx and laynx and useful in difficult intubation. Cinical study of LMA No. 2 was done in 30 children weighted between 8.9-26 kg, about cardiovascular changes, volume and pressure changes of inflaton cuff, problems and complications during insertion and maintaining of LMA. The result, were follows I) The average time taken to insert the LMA was 7.4±3.3 second and 12 case were correct placement at the second attempt to use laryngoscope. 2) The volume of inflation cuff without air leak during positive pressure ventilation with 15cmH2O of peak airway pressure was 7.9±0.5ml and inflation cuff pressure at insertion was 40.1±15.9 mmHg and increased(p<0.05) continously. 3) Mean arterial pressure was increased(p<0.05) compared with preinduction value and normalize within a minute. Heart rate was incresed(p<0.05) compared with preinduction value and increase was sustained. 4) There were no complications except 1 case of gastric disteesion.