The effect of liver transplantation (LT) on the severity and mortality of coronavirus disease 2019 (COVID-19) remained controversial. There is still no consensus on whether liver transplantation (LT) recipients with COVID-19 are at greater risk of developing severe or fatal COVID-19. It is not completely clear what is the course of the disease and what laboratory changes occur. The present study was undertaken to identify the dynamic changes in blood parameters of LT recipients pre and post COVID-19 infection which may be used to diagnose the severity and thus assess the prognosis of such patients. Our collected data are from a Bulgarian liver transplantation program at a single center for adult recipients of LT who were followed up from May, 2020, through May, 2022 in the pandemic environment. The current study aims analyzing the statistically significant differences in over 50 biochemical blood parameters in the cohort of LT recipients pre and post SARS-CoV-2 infection.