Investigation of the hemorheology and hemostasis system in patients with stroke of various types, location, and severity as well as with and without venous thromboembolic complications (VTECs), who were treated at critical and intensive care units, demonstrated the significance of impairments in the hemorheology and hemostasis system for VTEC pathogenesis in stroke patients. Despite ongoing anticoagulant therapy, aggravation of the prothrombogenic state was observed in VTEC patients. Ischemic stroke was associated with more severe changes compared to hemorrhagic stroke. Hemostasiological predictors of VTEC were identified. In patients without VTEC, both the coagulation and anticoagulation systems as well as the fibrinolysis system were preserved. The D-dimer and thrombophilia markers, such as hyperhomocysteinemia and antiphospholipid syndrome, were shown not to contribute to the development of VTEC in stroke patients.