Objective evaluation of the performance of autofluorescence bronchoscopy based on analysis of thin sections of the bronchus of resected lungs was performed and compared with the results of preoperative autofluorescence bronchoscopy. Conventional bronchoscopy and autofluorescence bronchoscopy were performed prior to surgery for lung cancer. Thin sections of the bronchus were obtained from the resected specimens. The thin sections were pathologically analyzed and the diagnostic accuracy of endoscopy was calculated. The subjects were 30 consecutive operable lung cancer cases who received white light and autofluorescence bronchoscopy before operation. A total of 163 thin sections of the bronchi in the resected lungs were made. The sensitivity of white light bronchoscopy for cancer was 90 and 31% for dysplasia. The respective figures for autofluorescence bronchoscopy were 97 and 50% for cancer and dysplasia. The specificity of white light and autofluorescence was 88 and 84%, respectively. The diagnostic accuracy of autofluorescence bronchoscopy was objectively confirmed. Autofluorescence examination showed better sensitivity for cancerous/precancerous lesions and the evaluation of the extent of cancer invasion was accurate.