The COVID-19 pandemic has resulted in a huge spread of disease worldwide, but with very different outcomes. The development of severe disease and mortality are more common in the elderly, men and those with comorbidities. Genetic mutations of immune system factors have been shown to be closely associated with an increased risk of severe COVID-19. A special role in the severity of COVID-19 is attributed to pro-and anti-inflammatory cytokines, the excessive secretion of which ultimately leads to endothelial dysfunction causing damage to vital organs, especially the lungs. Therefore, identifying a defect in COVID-19-related pro-and antiinflammatory cytokine gene variability is crucial for predicting the risk of disease progression. The aim of the study was to investigate the polymorphic variants of , , IL-10 (G-1082A), , and IL-4 (C-589T) genes in COVID-19 patients. We examined 142 patients with proven diagnosis of COVID-19. The control group consisted of 72 healthy donors. Real-