Chronic spontaneous urticaria is accepted as a systemic inflammatory disease. ABO blood groups are useful and valuable resource for researches because the inheritance of blood groups is not affected by any environmental factors. To our knowledge, the association between chronic urticaria and blood groups has not been understood properly. The aim of this study was to investigate the association between ABO blood groups and chronic spontaneous urticaria. It was a retrospective observational study. 139 patients with chronic spontaneous urticaria and 286 healthy control were included in this study. In the study 63 patients had type A (45.3%), 18 patients had type B (12.9%), 2 patients had type AB (1.4%) and 46 patients had type O (40.3%). When the control group is investigated in terms of ABO blood groups, 121 people were type A (42.3%), 49 people were type B (17.1%), 18 people were type AB (6.3%) and 98 people were type O (34.3%). There was no significant relationship between ABO blood group and patient or control group (X2=6.856, p=0.077). However, there was a significant relationship between the Rhesus (Rh) factor and patient and control group (X2 = 4.02, p=0.045). There wasn’t an association between blood groups and chronic spontaneous urticaria. Hovewer we established that the number of patients with Rh(-) blood group increased and the number of patients with Rh(+) blood group decreased in chronic spontaneous urticaria group. Further researchs are needed to understand the association.