Under observation were 175 patients with ovarian tumors and cysts. The distribution of ABO blood groups and Rh factor in relation to this pathology was studied as compared with the control series (2000 healthy females). There was noted an increased probability of the incidence of the majority of the ovarian tumor types among AB blood group females compared with other groups (O, A and B), and just the opposite, the probability of the tumoriform processes incidence in AB group females is considerably less than in other groups. The probability of ovarian tumors malignification proved to be the least in B group females. There is noted a considerably increased relative ovarian tumor and cyst morbidity among Rh-positive females compared with Rh-negative ones.