In the period of 20 years, the author had an opportunity to observe 14 cases of endothelial neoplasms of the lungs. The group consisted of eight women and six men, differing in age from 18 to 75 years. These cases presented as two subsets: low grade malignancy epithelioid hemangioendothelioma (PEH) (12 cases--eight women and four men, aged between 18 and 75 years) and highly malignant endotheliosarcoma seen in two men, 28 and 47 years old. The patients with epithelioid hemangioendothelioma reported to hospitals mainly because routine chest X-ray examinations accidentally revealed nodular lesions involving both lungs. Histological examination of the material collected from the bronchi and sputum was negative for neoplasm. The patients were suspected of suffering from tuberculosis or sarcoidosis and in some cases therapy was even initiated. Correct diagnoses were established based on histological examinations of material from the lesions taken during thoracotomy or thoracoscopy. In these cases, the course of the disease was slow and the patients were in a good condition for many years. In one case (a 27-year old woman), the diagnosis was possible after autopsy. The morphological appearance of these tumors is very characteristic. In case of any doubts, we can perform immunohistochemical examinations using endothelial markers, mainly CD34, possibly CD31 or factor VIII. Highly malignant endothelial sarcomas were seen in two men with a poor clinical status; one of them died shortly after histological diagnosis had been established based on material taken during a thoracotomy. In the second case, the diagnosis was possible on autopsy The prognosis for patients with these highly malignant tumors is highly unfavorable.