A bronchoscopy oxygenation system having a channel for inserting alternately an instrument or fluids and for delivering oxygen to a patient. The system being provided with pressure relief vent and a pressure relief valve for the relief of excessive oxygen pressure. The bronchoscopy oxygenation system may be used during bronchoscopy and with patient suctioning, bronchoalveolar lavage or biopsy. The bronchoscopy oxygenation system is intended to be used with a conventional bronchoscope.