In patients with COVID-19 pneumonia, high risk of thrombosis became a current issue, and D-dimer levels indicating fibrin degradation products (FDPs) in the plasma were found as a predictor for mortality. Although unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) decrease the production of FDPs by inhibiting factors Xa and II, they cannot contribute metabolization of existing FDPs. Furthermore, FDPs cannot be filtered by known cytokine filters because of their molecular weight (minimum 240 kDa). Yet, FDPs can be removed by therapeutic plasma exchange (TPE). Therefore, recently, three consecutive TPE sessions were performed in selected patients with COVID-19 pneumonia in intensive care units (ICUs) after the assessment of their clinical and coagulation status. In the study, the effect of TPE on outcomes was retrospectively investigated in patients with COVID-19 pneumonia.