Theileriosis encountered frequently in Van region and causes huge economic losses in cattle, sheep and goats. This study was carried out to examine the serum biochemical profile and serum protein fractions, determined before and 7 days after buparvaquone treatment, in 28 cattle, diagnosed to be infected with T. annulata and in 15 healthy control animals from the same region. The ALT (alanine amino transferase) and ALP (alkaline phosphatase) activities and the concentrations of bilirubin and urea were markedly increased in sera from infected animals whereas the concentrations of glucose, minerals (Na, K and Ca), total proteins, albumin and of a-globulins and the albumin/globulin (A/G) ratios were significantly depressed compared to the controls. In addition, buparvaquone treatment succeeded in alleviating the serum biochemical anomalies. These results show that liver and kidney failures occur during theileriosis leading to a global protein deficiency and that serum biochemistry and serum protein analysis may allow biochemical evaluation of treatment.