A balloon-tipped, wire-guided double lumen, endobronchial blocker catheter (6) is provided for insertion into the tracheal bronchial tree using a fiberoptic bronchoscope (2). The catheter incorporates a removable wire guide (14), which runs the entire length of the catheter exiting the tip as a small unencased wire loop (12). The small unencased wire loop is positioned around the circumference of a fiberoptic bronchoscope and when advanced along the fiberoptic bronchoscope thereby allows the catheter to navigate the airway using the fiberoptic bronchoscope as a guide or stint allowing the catheter to reach portions of the lung where access is difficult due to sharp bends in the tracheal bronchial tree. A balloon (8) thereof is inflated to provide obstruction of a portion of the lung from ventilation. The long wire guide loop is removable allowing communication of the blocked segment with the proximal end of the catheter.