Aims and objective: The novel COVID-19 virus infection is known to be a multisystem disease. Moderate and severe forms of COVID-19 are usually accompanied by damage to the lungs and blood vessels, but the heart, kidneys, liver, intestines, and pancreas can also be affected. Many biochemical parameters have been shown to become altered in COVID-19 patients in correlation with the disease severity and outcome. The aim of the study was to evaluate the significance of some biochemical parameters of blood characterizing kidneys and liver functioning as markers of mortality risk in patients with COVID-19, depending on their gender and age. Material and methods: A cohort, retrospective, cross-sectional study was conducted, which analyzed the clinical data of 195 hospital patients with a confirmed diagnosis of COVID-19 and pneumonia. The cohort was divided into groups by gender and age category. Biochemical parameters characterizing kidneys and liver functioning were analyzed: aspartate aminotransferases, alanine aminotransferases, total bilirubin, conjugated bilirubin, glucose, creatinine, urea. For correlation and statistical analysis, visualization of the results, the python language was used. The significance of differences in the parameters when comparing patient groups was assessed using one-way ANOVA and Student’s t-test. Results: The COVID-19 mortality rate was shown to increase with the age of patients. Among the patients over 50 years of age, the women mortality was 2.3 times lower than that of men. For the entire cohort, the mortality was determined to mostly correlate with the level of creatinine (correlation coefficient Kc=0.21) and urea (Kc=0.16). Analysis by age group showed that for patients older than 65 years an increase in creatinine by 2.5 times and urea by 2.2 times relative to the norm was associated with the 100 % mortality. Analysis by gender group indicated that the poor outcome of men is most associated with the increase of age (Kc=0.34), creatinine (Kc=0.27), urea (Kc=0.27); the similar correlations were not observed in women. Conclusion: It was found that an increase in creatinine level in COVID-19, indicating kidney damage, is more typical for men than for women (p=0.002). Creatinine >287 µmol/l and urea >18.3 mmol/l are the markers associated with the risk of COVID-19 related death in men over 65 years of age.