Bovine theileriosis is a destructive disease that affected cattle of all ages, breeds and sex and leads to severe losses in production and reproduction. To assess the antioxidant status and oxidative stress in bovine theileriosis due to Theileria annulata, blood samples were collected from 17 clinically infected cattle referred to the Veterinary Teaching Hospital, Assiut University. Complete blood picture, Nitric oxide, Malondialdehyde and total antioxidants capacity were determined and the results were compared with those of 10 healthy controls. The concentration of Nitric oxide (NO), Malondialdehyde (MDA) were significantly higher (P < 0.0001) and the total antioxidant capacity (TAC) was significantly lower in the infected cattle than in healthy ones (P < 0.001). Conventional and molecular techniques will help in early and accurate diagnosis and enables the effective treatment. The treatment with buparvaquoneaims to eliminate the parasite from the blood and lymph node and consequently improvement in the clinical state without any adverse effect on the animal's cells. After treatment noticeable improvement was observed in clinical signs and significant increase in total RBCs count (6.58 ± 0.98 x10⁶/mm³⁾ and hemoglobin concentration (9.82 ± 0.98g/dl) compared with (4.37 ± 2.05 X10⁶/mm³ and 6.67 ± 2.76 g/dl) before treatment, respectively. Also, the oxidative stress was significantly altered and a significant increase of the (TAC), significant decrease of (NO) and (MDA) was noticed.