One-lung ventilation is used to facilitate thoracic and cardiac surgery. This article describes the development and clinical use of a new device, the bronchial blocker tube, to establish one-lung ventilation. The bronchial blocker tube has two circular lumen joined together, one for ventilation and one for acceptance of a bronchial blocker. In this setting, the bronchial blocker is a separate device which is replaceable, rotatable, and removable. In the authors' experience, the bronchial blocker tube was effective and easy to use.