At the end of 2019, an infectious disease was discovered, has spread rapidly throughout the world, and has become a pandemic called COVID-19. Several risk factors for COVID-19 infection are advanced age and comorbid diseases. However, at the beginning of the pandemic in Wuhan, China there were more patients with blood type A who were confirmed positive than other blood types. The study aimed to analyze the relationship between ABO blood type and the severity and characteristics of COVID-19 patients at Universitas Airlangga Hospital, Surabaya. This study is a retrospective study, using secondary data in the form of medical records of Covid-19 patients at Universitas Airlangga Hospital, Surabaya. From the 104 COVID-19 patients at Universitas Airlangga Hospital, the majority are male (54.8%). Most of the ages are in the range of 45-59 years (37.5%). Most COVID-19 patients at Universitas Airlangga Hospital have blood type O. The most severe degree of infection of COVID-19 patients at Universitas Airlangga Hospital is the severe category (59.6%). There is no significant relationship between ABO blood type and the severity of COVID-19 infection statistically, but blood type O (37.5%) is the most common blood group in all degrees of severity, but blood type B is the most common group in cases of death. (28.1%). There is no significant relationship between ABO blood type and the severity of COVID-19 infection. The characteristics of COVID-19 patients at Universitas Airlangga Hospital are mostly male, aged 45-59 years, and blood type O.