This study was conducted to determine the relationship between the degrees of anemia and blood gases in cattle with theileriosis. It included 28 cattle with theileriosis and 7 healthy animals as the control group. The cattle with theileriosis were divided into 4 groups according to their hematocrit (Hct) values: cattle with Hct of >26 were considered as nonanemic (Group 1), Hct of 20-26 as mildly anemic (Group 2), Hct of 14-19 as moderately anemic (Group 3), and Hct of 10-13 as severely anemic (Group 4). The PCO2, HCO3, and TCO2 levels in the study groups were lower than those of the control group. Moreover, reductions in HCO3 and TCO2 concentrations were significant only in the severely anemic group. Similarly, the lowest PCO2 levels were also detected in the severely anemic group. There were no significant differences in the SO 2 levels between the control and study groups. On the other hand, the increase was significant in the severely anemic group when compared to Groups 1 and 2. The results seemed to indicate the trend of uncompensated metabolic acidosis in theileriosis cases with severe anemia; thus, veterinary surgeons should bear this in mind when evaluating the prognosis for such cases.