A statistically comparison of the professions on 1119 male patients with malignant laryngeal tumours and the profession on 708 male patients with malignant tumours of stomach, shows the influence of occupational exposures. The quantity of malignant laryngeal tumours is high in the group of steelworks -and foundry workers, workers in the glass-, porcelain-, quartz- and chemical industry and motorists. The inhalation of exogenous cancer-poisons are the cause probable.