The aim of this study was to determine the associations of the polymorphisms rs2070788, rs75603675 and rs12329760 of the TMPRSS2 gene and the polymorphisms rs2227631, rs2227667, rs2070682 and rs2227692 of the SERPINE1 gene with COVID-19 severity and their relationships with inflammatory biomarkers. Here, SERPINE1 is linked to COVID-19.