The study of 112 case histories of lung cancers, both primary and secondary, has allowed the authors to determine as being of 5% the incidence of primary bronchogenic carcinoma associated with treated pharyngo-laryngeal cancer. One out of three such primaries was a solitary lung opacity. Bronchogenic primaries appeared be almost as frequent as lung, pleura and mediastine secondarie. They can be diagnosed at any moment of the treatment or follow-up of pharyngo-laryngeal cancer, and appear to occur later than pulmonary metastases. Their symptoms are more "bronchopulmonary" in nature. They are more frequently associated with endolarynx and chorda carcinomas. They are possibly more frequent in cases of smaller primaries without lymph-node involvement. Solitary lung opacities should be considered as independent primaries and constitute the best candidates for efficient pulmonary treatment. Treated pharyngo-laryngeal patients should undergo regularly spaced lung roentgenograms and frequent tracheal sputum cytology.