Patients with severe sepsis have multiple dysfunction of coagulation system [1]. The routine coagulation tests provide possibility to estimate plasma part of system of coagulation, but without estimation of specific cellular part of this system. Appearance of new global coagulation tests provides assessment of physical characteristics of the clot and kinetics of it formation, so as fibrinolysis and retraction of clot. The clinical study of coagulation system has been conducted in order to estimate the roll of the thrombocytic fraction, which causes the disturbance of coagulation in patients with sepsis and septic shock. The patients have been divided into two groups: Group 1 consisted of 26 patients without thrombocytopenia. As Group 2 we enrolled 18 patients with this disturbance. The routine coagulation tests (prothrombin index Quick s value, activated partial thromboplastin time (aPTT), fibrinogen testing included), platelet count and assessment of platelet's morphology and thromboelastography has been completed in every patient. Results: parameters of routine coagulation tests show no dependence of platelet count. Also, during the estimation of parameters of thromboelastogram has been noticed that patients with thrombocytopenia had increased clot reaction time (R), clot kinetics (K, time from clot formation to time amplitude reaches 20 mm), decreased value of angle a and maximum amplitude (MA). Based on data obtained during study, may be assumed that for patients with sepsis and septic shock are characteristic deficit of the coagulation proteins are the core components of the coagulation system and activation of cellular part of coagulation system. Developing of thrombocytopenia does not lead to manifest hypocoagulation. Using both routine coagulation tests and thromboelastinography in interpretation of results gives us better insight of complex assessment of system of coagulation and provides guideline in treatment of those patients.