Introduction. Rotation thromboelastometry (ROTEM) is a method for studying haemostasis at the place of providing care, which allows identification of disorders on the basis of extrinsic and / or intrinsic coagulation pathways.Aim. To study the possibility of using ROTEM for diagnosing the deficiency of individual blood coagulation factors, as well as for monitoring the efficacy and safety of haemostatic therapy in such coagulopathies.Materials and methods. The study included 9 patients with a congenital deficiency in various coagulation factors. The authors performed ROTEM, as well as coagulological tests to determine activated partial thromboplastin time, Quick’s value, fibrinogen and the plasma activity of coagulation factors FV, FVII, FVIII, FIX, FXI and FXII. In order to exclude the effects of heparin or hyperfibrinogenaemia, HEPTEM and / or FIBTEM were conducted. In order to identify the deficiency of individual coagulation factors, the authors used standard plasma samples and plasma deficient in one of the coagulation factors. The citrated blood under study was mixed with standard plasma and that deficient in one of the studied factors in a 2:1 ratio for subsequent repetition of the EXTEM and / or INTEM tests. Coagulation factor deficiency was confirmed by a change in the CT parameter.Results. Isolated prolongation of EXTEM CT was detected in the setting of FVII deficiency; while INTEM CT prolongation occurred under the deficiency of FVIII, FIX, FXI, FXII, with simultaneous EXTEM and INTEM CT prolongation being observed in the context of FVII deficiency. The test of a mixture of citrated blood and standard plasma revealed shortened EXTEM CT in the setting of FVII deficiency and shortened INTEM CT under the deficiency of FVIII, FIX, FXI, FXII, with the shortening of both EXTEM and INTEM CT being detected in the setting of FV deficiency. In a sample containing a mixture of whole blood and plasma deficient in the studied factor, CT remained prolonged or increased. Clinical examples of using ROTEM for diagnosing coagulation factor deficiency are presented.Conclusion. The normalisation of ROTEM parameters in a standard plasma sample along with the preservation of hypocoagulation in a factor-deficient plasma sample confirms the coagulation factor deficiency. ROTEM provides the possibility of monitoring the efficacy of haemostatic therapy for congenital deficiencies in individual blood coagulation factors.