Diagnostics of intrathoracic sarcoidosis in people with an occupational injury or an annoyance of respiratory organs are frequently connected with additional difficulties. The first roentgenological manifestations of a silicosis caused during the period of dry drilling especially in ore metal mining, are frequently bilaterally increased shadows of the hilum without any worth mentioning findings in the parenchyma. The radiograph of diffuse restiform and speckled shadows in people exposed to dust without a sufficient load or in younger age always demands a search for sarcoidosis. Granulomatoses of the lungs caused by organic dusts, berillium and other things may develop difficulties not only in the interpretation of clinical data but also in the bioptic findings for instance after an endoscopic antalgic biopsy of the bronchomucosa. The authors summarize their experiences with the application of bioptic methods (skin biopsy, according to the Kveim-test, scalenobiopsy, explorative thoracotomy) in workers suspected to suffer from a sarcoidosis, who--as to their profession--had been influenced by noxious substances in respect to their lungs. Two typical cases are briefly discussed. The signification of the synopsis of clinico roentgenological, industriohygienical and bioptical data is stressed especially in case of a suspicion on the combination of pneumoconiosis and sarcoidosis.