Patients (48) with primary bronchial carcinomas were examined, and 41 of these carcinomas (85%) were confirmed by histopathological or cytological tests on samples taken during flexible fiberoptic bronchoscopy. Thirty-seven patients (77%) were diagnosed histopathologically, based on forceps biopsy, and 4 cases cytologically, based on investigations of bronchial secretions and brush biopsies. In 9 of 14 patients with peripheral tumors, the diagnosis was verified by flexible fiberoptic bronchoscopy. This a very safe and useful method in the early diagnosis of bronchial carcinoma.