AIM: The aim of this study is to analyze the prognostic significance of ABO and Rh blood group antigens along with various parameters in patients followed-up with the diagnosis of COVID-19. METHODS: We evaluated 397 patients who were follow-up and treated due to COVID-19 infections. The ages, genders, chronic diseases, ABO and Rh blood group antigens, admission rates to Intensive Care Units (ICU), and mortality rates of the patients were analyzed. FINDINGS: The mean age of the 397 patients with COVID-19 was 47+/-17 years. In the blood group analysis of the patients, A Rh-positive (A +) was the most frequently seen blood type (176 patients, 44.3%) followed by O Rh-positive (0 +) (109 patients, 27,5%); 38 patients were Rh negative (Rh -) (9,6%). 53 of the patients (13,4%) were followed in ICU and 29 patients died (7,3%). Neither mortality nor admission to ICU was seen for Rh - group. The comparison of Rh groups concerning the need for ICU admission revealed a significantly high rate of ICU admission in the Rh + group (p=0,011), while no significant relationship was found between mortality and Rh antigen (p=0,069). CONCLUSION: The most frequently seen blood type among COVID-19 patients was A +. The Rh + blood group was found in all cases who were admitted to ICU and had a death outcome. The Rh + blood group was found in a significantly high number of patients who were admitted to ICU, while no significant relationship was found between mortality and Rh blood group.