Flexible fiberoptic bronchoscopy is the most useful invasive technique for diagnosing lung cancer. This article details the use and efficacy of bronchoscopy with such established techniques as forceps biopsy, brush biopsy, and bronchial washing in the diagnosis and staging of bronchoscopically visible central lung cancer and peripheral lung cancer. The efficacy of such newer techniques as transbronchial needle aspiration, transbronchial curettage, ultrathin fiberoptic bronchoscopy, and quantitation of tumor markers in bronchoalveolar lavage fluid is also discussed, along with the complications of bronchoscopy and new techniques for detecting early lung cancer.