IntroductionGiven the rapid spread, significant morbidity and mortality associated with COVID-19, there has been scientific interest in obtaining data detailing the factors influencing the risk of COVID-19 infection. The aim of this study was to reveal a possible association between the ABO-RH system and the risk of COVID-19 in the Moroccan population.Materials and methodsThis is an analytical cross-sectional study. It was carried out on 1094 patients for the diagnosis of Covid-19 by Rt-PCR at the Moulay Ismaïl military hospital in the province of Meknes. All Rt-PCR negative individuals were used as a comparison group.ResultsAmong the 1094 individuals who were diagnosed, RT-PCR for detection of SARS-CoV-2 was positive for 242 individuals. Comparison of the proportions of blood groups of the two groups showed that the proportion of blood group A in patients with COVID-19 was significantly higher than in people in the comparison group (P = 0.007), while the proportion of blood group O in patients with COVID-19 was significantly lower than in people in the control group (P = 0.017). Comparison of the Rh blood groups of the two groups did not find a significant association (P = 0.608).ConclusionAs demonstrated by several previous studies, we concluded that blood group A was associated with a higher risk of acquiring COVID-19. Equally, the O blood group was associated with a lower risk of infection.