Objectives: Inflammatory mechanisms play an important role in the pathogenesis of cerebral ischemia and in the risk of stroke. In several studies, elevated leukocyte count has been associated with cardiovascular and cerebrovascular events. The aim of this study is to investigate the relationship between the leukocyte and neutrophil counts and stroke severity, short term prognosis and stroke subtypes of the patients with acute ischemic stroke.Materials/Methods: Leukocyte and neutrophil counts were measured in 166 consecutive acute ischemic stroke patients in the first 24 hour of admission. Clinical findings, stroke risk factors and brain imagings were evaluated. According to their etiology, patients were classified by using the TOAST criteria. Stroke severity was assessed by the modified Rankin Scale(mRS) on admission and discharge, National Institutes of Health Stroke Scale (NIHSS) was used on admission.Results: While 51(%30.72) patients had leukocyte ≥10000/μl and 115(%69.28) patients had leukocyte <10000/ μl, 70(%42.17) patients had neutrophil ≥6100/μl and 96(%57.83) patients had neutrophil<6100/μl. leukocyte and neutrophil counts were significantly higher in severe stroke (p<0.001) hence short term prognosis was significantly poor in these patients. (p<0.001) We found a strong correlation between large vessel disease and high leukocyte count (p<0.05) and also between small vessel disease and normal leukocyte count. (p<0.05) Results were similar for neutrophil levels of patients according to stroke subtypes.Conclus on: According to our study; high leukocyte and neutrophil levels on admission correlate with large vessel disease and therefore could be a predictor of stroke severity and unfavourable outcome.