Background: The combination of endobronchial biopsy with cytological brushing is considered the best procedures for the diagnosis of lung cancer during bronchoscopy. Aim: To asses the diagnostic yield for lung cancer (with visible endobronchial alterations at endoscopy) of three fiberoptic bronchoscopy procedures: endobronchial biopsy, cytological brushing and bronchial cytological washings. Material and Methods: Prospective study of 160 consecutive patients referred for fiberoptic bronchoscopy for clinically suspected lung cancer. Sequential bronchial washing, brushing and biopsies, were performed to all patients with a visible endobronchial alteration. Results: One hundred and nine patients had a visible endobronchial alteration at fiberoptic bronchoscopy, but only 86 of them completed the protocol (21 patients were not subjected to the three diagnostic bronchoscopy procedures, because of bleeding or tolerance problems, and in two patients all the data required was not available). In twenty three, the diagnosis was a benign lesion, whereas lung cancer was diagnosed in 63. Fifty four of these 63 patients had at least one of the three endoscopic procedures (endobronchial biopsy, cytological brushing and bronchial cytological washings) positive for lung cancer (85.7%). The association of endobronchial biopsy with cytological brushing was positive for lung cancer in 49 cases (78%), and was the best association of two procedures. The diagnostic yield of each procedure was: endobronchial biopsy 50/63 (79%), cytological brushing 18/63 (28.5%). Conclusions: The best yield for the diagnosis of lung cancer is obtained with the association of the two procedures (endobronchial biopsy, cytological brushing). Cytological washings have a very low diagnostic yield (Rev Méd Chile 2004; 132: 1198-203)