The purpose of this study is to evaluate the application of high frequency percentaneous transtracheal ventilation and high frequency jet insufflation for suspension laryngomicrosurgery under general anesthesia. Twenty patients were anesthetized with intermittent intravenous anesthetics and paralysed with d=tubocurarine or pancuronium. The patients were divided into two groups. In group l (n=8) ventilation was through 16G Anglocath introduced into the trachea through the cricothyroid membrane and in group 2 (n=12) ventilation was through a 5 mm endotracheal catheter insertion. A respiratory rate of 100/min. was used at an FiO2 1.0 using a solenoid valve actuated ventilatior. The inspiratory expiratory ratio was 1:2. The driving pressure of oxygen was 10~15 psi. In both groups there was no significant change in the following parameters compared to starting control values(pH, PaCO2 and PaO2). But cardiovascular parameters such as blood pressure and heart rate were slightly increased. The data obtained from this observation indicate that these techniques and devices, used properly, should provide adequate ventilation and an improved visual operative field.