Background: SARS-CoV-2 infection is clinically very heterogeneous, varying from asymptomatic to severe clinical conditions with a fatal outcome. Some studies suggests that the ABO blood group could be a biological marker of susceptibility for the development of the disease. Material and methods: We collected data from patients admitted with COVID-19 infection who had ABO blood group recorded, and analyzed the incidence by groups, compared with the global population in Navarre, as well as their main complications and evolution. Results: Group O was proportionally less represented in the hospitalized patients with respect to the global population, although the difference was not statistically significant. Group B had significantly higher rates of thrombotic complications and required more admissions in intensive care units. Conclusion: The study suggests a lower susceptibility to infection in group O and a higher risk of complications in group B. Studies with a larger sample size are required in order to obtain significant results.