Malign disease are an important risk factor in case of disorder of hemostasis mechanisms. Both malignancy and disorder of the function of hemostasis system in connected with the occurrence of a whole range of abnormalities in the population of patients . It includes disorder of the partial thromboplastine time, increase of level of coagulation factors in plasma, acceleration of transformation of fibrinogen, megacariocit hyperplasia, thrombocytosis, effect of tumor necrosis factors to endotel, effect of tissue factor-like procoagulant etc. The goal of study determine frequency of thromboembolia in patients with malign hematological diseases. Diagnostic protocole includes clinical picture, and laboratory tests along with relevant parametres for assesment of coagulation status of patients. Results deviate from obtained results in studies that analyse other malignancies. The authors find explanation in the specific characteristics of malign hematological diseases and treatment. The cause of disorder of the function of hemostasis system is in quantitative deviation of thrombocytosis, change of body vessels wall or global "break down" of this system which is demonstrated with disseminated intravascular coagulation (DIK).