Aim To study specific features of the parenteral anticoagulant therapy for acute myocardial infarction (MI) in the Russian Federation and to evaluate the consistency of the prescribed parenteral anticoagulant therapy with the effective clinical guidelines.Material and methods REGION-MI, the Russian rEGIstry for acute myOcardial iNfarction, is a multicenter observational study. This registry includes all patients admitted to hospitals with a documented diagnosis of ST-elevation acute MI (STEMI) and non-ST-elevation acute MI (NSTEMI) based on the criteria of the Forth Universal Definition of MI of the European Society of Cardiology. Risk of bleeding was assessed with the Academic Research Consortium for High Bleeding Risk (ARC-HBR) scale, and risk of major bleeding in patients with NSTEMI was additionally assessed with the CRUSADE scale.Results From November 01, 2020 through April 03, 2022, 5025 patients were included into the REGION-MI registry. At primary vascular departments, 70.5% of patients were administered unfractionated heparin (NFH); at regional vascular centers, 37.1 % of patients were administered NFH, 29.6 % enoxaparin, 20,2% NFH in combination with enoxaparin, 6.8 % fondaparinux, 4.2 % NFH in combination with fondaparinux, and 1.9 % nadroparin. At the prehospital stage, NFH was used as an anticoagulant support for the thrombolytic therapy (TLT) in 84% of patients, and low-molecular heparins (LMH) were used in 16 %. At the hospital stage, UFH was administered to 64.4 % of patients, and enoxaparin was administered to 23.9 % of patients. Among the patients who had undergone primary percutaneous coronary intervention (PCI), 40 % received NFH, 25 % enoxaparin, 22 % NFH in combination with enoxaparin, 7 % fondaparinux, and 4 % NFH in combination with fondaparinux. In conservative and invasive tactics of therapy for NSTEMI, NFH was also administered more frequently (43 and 43 %, respectively), followed by (according to frequency of administration) enoxaparin (36 and 34 %, respectively), NFH in combination with enoxaparin (10 and 16 %, respectively), fondaparinux (7 and 6 %, respectively), and NFH in combination with fondaparinux (3 and 1 %, respectively).Conclusion According to the Russian registry of acute MI, REGION-MI, with all strategies for the treatment of MI, parenteral anticoagulants are not prescribed in full consistency with clinical guidelines. The most frequently used parenteral anticoagulant is NFH. Despite the high efficacy and safety of fondaparinux, the frequency of its administration remains unjustifiably low not only in the Russian Federation but also in other countries. The same can be said about the administration of enoxaparin to patients who had received TLT. Attention should be paid to physicians' awareness of recent clinical guidelines, to minimize the prehospital treatment with parenteral anticoagulants, to limit this treatment to the TLT support, and to provide continuity between all stages of medical care.