Updated project metadata. The disease caused by the novel coronavirus of 2019 (COVID-19) has resulted in significant morbidity and mortality world-wide. A systemic hyper-inflammation characterizes the severe COVID-19 disease often associated with acute respiratory distress syndrome (ARDS). Bloodbiomarkers with prognostic relevance are of great importance in effective triage and critical care of severe COVID-19 patients. In the present study we report higher plasma abundance of soluble urokinase-type plasminogen activator receptor (sUPAR), shown to be expressed by an abnormally expanded circulating myeloid cell population, in severe COVID-19 patients with acute respiratory distress syndrome. SUPAR level was found to be linked to a characteristic proteomic signature of plasma. A receiver operator characteristics curve analysis identified a cut-off value of sUPAR at 2000pg/ml, which was linked to characteristic differential expression in the immune transcriptome as well as clinical outcomes in our patient cohort. Thus we identified sUPAR as a biomarker with strong predictive potential for clinical outcomes in severe COVID-19.