Анотация: Significant changes in total blood white blood cells (WBC) and populations are found in many generalized and localized pathological conditions in veterinary medicine. Endometritis is an inflammatory process that might lead to infertility in mares and it is associated with an influx of polymorphonuclear neutrophils (PMN) into the uterine lumen. Endometriosis is a chronic degenerative endometrial disease that causes severe alterations in the connective tissues of the uterus. We took blood samples from 6 Carthusian mares with endometritis (EM1) and 8 with endometriosis (EM2) in order to check whether these changes lead to changes in hematology. Further, 6 healthy mares of the same breed and similar age were also sampled (control group, CG). An analysis of variance was used to evaluate the differences between the three groups of mares. In comparison with CG, mares of group EM1 had significantly higher hemoglobin concentration, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin concentration, segmented PMNs and neutrophils/lymphocytes ratio, and lower total white blood cells and lymphocytes. Mares of group EM2 presented lower red blood cell and white blood cell counts. No morphological changes were detected in the different types of WBC when examined in the blood smear. It is concluded that some hematological parameters differ in mares with endometritis and endometriosis in comparison to healthy mares. Even though the hematological study is not useful in the diagnosis of these diseases, the results of the present research are important in order to diagnose other clinical conditions that could coexist with these reproductive diseases