With the wide acceptance of laryngomicrosurgery, many different methods have been introduced for maintainance of adequate respiration and the provision of a clear operative field. Several anesthetic techniques, such as the following have been used for diagnostic or operative laryngoscopy ; Topical anesthesias, apneic techniques, chest respirators, neuroleptanalgesics and general endotracheal anesthetics with muscle relaxants. Besides other common surgical risks, laser surgery has the heat effect on the endotracheal tube. In this study, we selected twenty patients who were anesthized by high frequency jet ventilation with intermittent intravenous anesthetics combined with d-tubocurarine or pancuronium as muscle relaxants. In group I(n=8), ventilation was maintained through a 16G angiocath introduced into the trachea through the cricothyroid membrane and in group II(n=12), ventilation was through a 5mm endotracheal catheter. In order to classify the effect of the anesthesia, we took two aterial blood samples, the first, under FiO₂ 1.0 mask ventilation and the second, 15 minutes after high frequency ventilation. The results are as follows : 1) In both groups, there was no significant change in the following parameters when compared to the control values(pH, PaO₂, PaCO₂). 2) This technique proved itself to provide easy visualization of the larynx and good access for surgical manupulation. 3) Lastly, there were no significant complications with this procedure.