Ventilation during general anesthesia for bronchoscopy has recently been greatly improved by application of the Venturi principle. Ever since 1967 when Sanders published a paper describing the Venturi principle for ventilatory bronchoscopy, this technique has become increasingly popular. Many papers have been published promoting the use of the Venturi principle which in most cases entails a 16-gauge needle aimed distally down the proximal end of a bronchoscope through which a jet of oxygen is intermittently injected to produced positive pressure ventilation in the lungs. In our study, ten patients undergoing bronchoscopy were ventilated with the Venturi stsytem and the patients were bronchoscoped with a Karl Stors bronchoscope lined with a Venturi oxygen injecttimer, Freiberg 8585T, to which oxygen was supplied from an adjustable pressure reducing valve connected to pipeline oxygen at 55 psi. The following results were obtained: 1) Ten patients verying in age from 2 to 53 years were bronchoscoped becaeuse of subglotticedema, granuloma, emphysems, and tracheal stenosis. 2) The internal diameter of the bronchoscopes varied from 3.0mm to 6.5mm and the inflation pressure varies also from 0.4bar to 1.0bar. The inspiration to expiration time ratio was 1:2 and 1:3. 3) The average PaO2 was well maintained during bronchoscopy and in the postanesthetic stage, but the PaCO2 was slightly increased over the preoperative values. The explanation for this result is that the bronchoscope fitted too tightly to the trachea, so that exhalation was incomplete, and the process of exchange inhibited the elimination of CO2 from the lungs. The results obtained from this study suggest that this technic and device, when used properly, should provide adequate ventilation and an improved visual isation of the operative field.