The incidence of thromboembolic disease (TED) in malignant diseases is high and is often the cause of death in these patients. The most important thrombogenic factors are changes of the coagulation system, venostasis, changes in the function and structure of the endothelium and the influence of specific anti-tumour therapy. The most frequent clinical manifestation is phlebot- hrombosis of the lower extremity. Diagnostic procedures in detection of thrombosis do not differ fundamentally from standard procedures (clinical examination, duplex sonography, phlebograp- hy, possibly pulmonary scintigraphy). More intensive prophylaxis of TED is necessary under certain conditions (surgical treatment, immobilization, chemotherapy). Therapeutic patterns with heparins, possibly thrombolytics, are common but subsequent anticoagulation treatment must be provided as long as the active stage of the neoplastic disease persists, in particular if the patient is treated with cytostatics. When anticoagulation treatment is contraindicated and there is a general favourable prognosis, implantation of caval filters is an adequate provision. New findings indicate the possible anti-tumourous action of low-molecular heparins, but these are only initial observations.

        Key words: Thromboembolic disease - Malignant disease - Etiopathogenesis - Prophylaxis – Treat-