The aim of this study was to investigate the relationship between ABO blood groups and the rate and severity of morbidity and mortality in patients with Covid-19 in Zahedan. The present study is a descriptive-analytical study and includes a sample of 349 patients with Covid-19 referred to hospitals in Zahedan from March 2016 to August 2017. The sampling method was census and for data collection, case studies and checklists were used. The data were analyzed by Chi-square test through SPSS software. Among the 328 patients, 132(41%) had blood type O, 92(28%) had blood type A, 80(24%) had blood group B and 24(7%) had AB blood type. There was no significant relationship between blood groups and age (P <0.150). Patients in the age group of 30-60 years with 208 (63.4%) had the highest number, of whom 78 (23.8%) had blood type O. There was a significant relationship between blood groups and gender (P = 0.001), so male patients with 178 (54.3%) were more, of whom 72 (22%) had blood type O. There was no significant relationship between blood groups and place of hospitalization (P <0.121); however, inpatient department patients with 150 (45.7%) had the highest number, of whom 62 (41.3%) had blood type O. There was no significant relationship between blood groups and severity of covid-19 (P <0.121); however, patients with moderate severity had the highest number with 150 (45.7%) patients, of whom 62 (41.3%) had blood type O.