Ovarian tumors are rarely seen in bitches and they usually occur in older ages. The most common type of ovarian tumor is epithelial tumors. Hematological parameters are frequently affected by the presence of neoplasms. There are various types of anemia associated with neoplasms. In the present study; we investigated the relationship between complete blood count (CBC) and the presence of ovarian tumors in bitches. Seven bitches with ovarian tumors and 6 bitches with histologically healthy ovaries were selected for this study. Increased level of platelet (PLT) was determined in bitches with ovarian tumors and considered as a significant finding to estimate the cancer progression. Besides, red blood cells (RBC), hematocrit (HCT), and hemoglobin (HGB) levels were decreased in bitches with ovarian tumors, which might be associated with cancer related anemia. In conclusion, the evaluation of complete blood count in bitches with ovarian tumors can be important to estimate the hematological effect of tumor progression.