BACKGROUND: Many studies have demonstrated that nitrous oxide diffuses into the cuffs of endotracheal tubes and increases cuff volumes and pressures. Such increments of cuff pressure maybe result in damage to the trachea. We evaluated the increase of intracuff pressure, volume and the statistical significance was analyzed with personal computer. METHODS: Fourty-nine patients ranging in age 37+/-15 years, in ASA physical status class 1~2 , they were 26 males and 23 females. They divided into two groups, group I(n=25) were anesthesia with nitrous oxide : oxygen (2 L/min : 2 L/min), group II were(n=24) anesthesia with nitrous oxide : oxygen (4 L/min : 2 L/min). The cuff pressure was measured every 30 minutes and compared with each others and group I and II. RESULTS: Our results suggest that a significant intracuff volume and pressure changes developed between two groups (p<0.05), more significant intracuff pressure changes occured at group II than group I (p=0.001) and significant increment changes according to time and different concentration of nitrous oxide between two groups (p<0.05). CONCLUSIONS: This study was conducted to determine the degree of intracuff pressure and volume changes during general inhalation anesthesia with different concentration of nitrous oxide. These results suggest that a nitrous oxide significantly increases cuff pressure and volume in a concentration and time related fashion.