Background The left atrial appendage (LAA) is known to be the primary source of thrombus formation in atrial fibrillation (AF). Our aim was to investigate if LAA elimination (LAAO) from the cardiovascular system has an effect on the coagulation and prothrombotic status in AF. Methods Twenty two patients with nonvalvular AF not currently on anticoagulation therapy participated in a single-center prospective study. We measured fibrinogen and plasminogen levels along with Ks, clot lysis time (CLT), and endogenous thrombin potential (ETP) before LAAO procedure, at discharge and 1 month follow-up. Results 1 month after the LAAO procedure compared to baseline value, we found Ks improved by 39.3% measured in clots prepared from peripheral blood (p=0.019) and also after adjustment for fibrinogen (p=0.027). Higher Ks was associated with improved clot susceptibility to lysis (r=-0.67, p=0.013). We found shortened CLT by 10.3% (p=0.0020); a 52% lower PAI-1 antigen levels (p=0.023) along with 8.9% increased plasminogen activity (p=0.0077). A tendency to decreased thrombin generation, reflected by decreased ETP and peak thrombin generated, was observed 1 month after the LAAO procedure (p=0.072 and p=0.087). No differences were found in tPA and TAFI plasma levels (both p>0.05). Conclusions We confirm, that LAA plays a key role in thrombogenesis and is the main source of thrombus in AF. LAA elimination from the circulatory improve fibrin clot permeability and susceptibility to fibrinolysis in peripheral blood.