Objective. To study the antioxidant status (AOS) of blood serum of patients in the acute period in patients with a variety of pathogenic forms of ischemic stroke (IS). Material and methods. A total of 99 patients (study group) with different types of ischemic stroke (IS): with atherothrombotic variant (n=74) IS, with cardioembolic (n=15) with lacunar type (n=10). The control group consisted of 15 persons. Total antioxidant status (TAS) in the blood serum was examined by the test system «General antioxidatic status — Novo» («Vector-Best», Russia) for 1—2 days from the onset of the disease. Results and Conclusion: Patients in the control group AOS was 1.69±0.17 mmol/L (median 1.72, interquartile range 1.53—1.83 mmol/L). With the development of IS AOS was 1.15±0,41 mmol/L (median 1.12; interquartile range 0.84—1.45 mmol/L) (p=0.000001). In groups with different pathogenetic mechanism of the IS value of the AOS was lower than in the control group and accounted for atherothrombotic variant (1.24; 0.98—1.67 mmol/L) (p=0.000001), for cardioembolic (p=0.000031), and for lacunar (1.24; 0.98—1.67 mmol/L) (p=0.035044). The value of the AOS was not significantly differ between men and women and was independent on the age and location of the ischemic lesion. Reduced AOS serum indicates an imbalance between prooksidatnoy and antioksidatnoy system in the formation of any pathogenic forms of IS. The decrease of AOS in blood serum indicates the balance between prooxidative and antioxidative system in the formation of any pathogenic forms of AI.