BACKGROUND: Coronavirus disease-2019 (COVID-19) causes severe hypoxemia. Unlike normal pneumonia, pneumonia due to COVID-19 causes oxygen deprivation without breathing difficulties (i.e., silent hypoxia). We evaluated the relationship between COVID-19 and hypoxemia and examined possible mechanisms of pneumonia from the perspective of gene expression (HIF1A, vascular endothelial growth factor [VEGF], NF-kB, MEKK1, and EGFR) using real-time PCR and ELISA for serum parameters. METHODS: We evaluated 100 individuals (50 patients and 50 controls). The patients were individuals with respiratory symptoms and pneumonia who were COVİD-19 positive. The relative quantification of standardized samples wa s calculated according to the formula 2 RESULTS: The fold change values of the HIF1A, VEGF, NF-kB, MEKK1, and EGFR genes were 0.048, 0.688, 0.168, 0.207, and 0.171, respectively, in the cases checked against to the controls. The areas under the ROC values indicating the diagnostic power of the genes were 0.727, 0.538, 0.815, 0.734, and 0.936, respectively. Some serum parameters were significant (age, PCR, urea, LDH, WBC, ferritin, and pO CONCLUSIONS: The upregulation of some genes in the hypoxia pathway in COVID-19 pneumonia shows that these genes and protein products are candidates for treatment targets. At the same time, the high discriminative power of two genes (NF-κB and EGFR) in patients compared to controls indicates their diagnostic potential in serum samples.