As many as fourteen children with teratodermoid tumours of the mediastinum were examined and treated at the department of surgery of developmental abnormalities of the Institute of Pediatrics, Obstetrics and Gynecology. Intrathoracal compression of the respiratory tracts caused by a ripe teratodermoid tumour was identified in 7 patients, by an unripe tumour--teratoblastoma--in one patient. Some specificities of intrathoracal compression of the respiratory tracts have been studied together with complications thereof.