the effect of chemotherapy treatment on hemostasis of patients with lung cancer chemotherapy is known to raise the risk of developing thrombotic complications the aim of our work is to study the system of hemostasis in patients with the lung cancer under chemotherapy treatment 61 patients were examined 40 men 21 women between the ages of 32 and 75 years the principal group chemotherapy was prescribed to 52 patients with the lung cancer considered as nonoperable ones and to 9 patients who refused surgical treatment chemotherapy applied to the patients was done by the conventional scheme the treatment has been conducted from 16 to 20 daysthrombocyticvascular hemostasis plasmatic hemostasis physiological anticoagulant activity the blood fibrinolytic activity markers of intravascular coagulation of the blood and those of fibrinolysis were studied the depletion of compensatory mechanisms at all segments of hemostasis in nonoperable patients was revealed the type of reaction points at an oppressive effect of chemodrugs on the hemostasis system and the increase of the risk of development thrombotic complications in those patients