An examination was made of the series of 439 lung tumours diagnosed ambulatorially at the Turin Social Health Dispensary to assess the diagnostic return from several techniques (cytology of the sputum, bronchial aspirate and brushing; histology on a biopsy specimen) used singly or in combination. It was also sought to determine the increase in sensitivity obtained by adding technique to each one other, and to establish the overall sensitivity of the protocol. It was found that biopsy was the most sensitive technique (91% in tumours visible by fibrobronchoscopy). The single cytological techniques displayed a lower sensitivity than in the literature, and there was no significant difference among them. The most sensitive combination was brushing + sputum (89.2%), while the sensitivity of the protocol as a whole was much the same as that reported in the literature. In the case of fibrobronchoscopically visible lesions, multiple biopsies (preferably 3) may be sufficient, whereas combination of the three cytological techniques is necessary to ensure acceptable sensitivity with regard to invisible lesions.