Lung cancer is the leading cause of cancer deaths in developed countries. Recently, autofluorescence bronchoscopy has been reported to improve the early detection of lung cancer in high-risk individuals. In the present study, we evaluated the efficacy of autofluorescence bronchoscopy for the early detection of bronchial premalignant and malignant lesions. From November 2000 through March 2004, 123 high-risk individuals (114 men and 9 women with a mean age of 68 years) were enrolled. Among 282 biopsy specimens, 93 (33.0%) were premalignant or malignant lesions. The sensitivity and negative predictive value for the detection of bronchial premalignant and malignant lesions were significantly higher with the addition of autofluorescence bronchoscopy than white light bronchoscopy alone. Moreover, the sensitivity for the detection of bronchial premalignant lesions was extremely higher with the addition of autofluorescence bronchoscopy than white light bronchoscopy alone, whereas there was no significant difference between autofluorescence bronchoscopy and white light bronchoscopy alone for the detection of non-malignant and malignant lesions. Autofluorescence bronchoscopy is a novel modality for the early detection of bronchial abnormality, especially for bronchial premalignant lesions.