Objective. To study the changes in endothelial dysfunction and von Willebrand factor activity in acute and chronic stages of hemispheric intracerebral hemorrhage (ICH) and their influence on clinical severity and functional recovery. Material and methods. Fifty patients with hemispheric ICH, aged 61.6±11.2 years, and 30 patients with AH, aged 59.6±6.2 years, (comparison group) were examined. Patients with ICH were examined on admission, 6—8th, 13—15th days, and 11.1±0.9 months after stroke onset. Patients with arterial hypertension (AH) were examined on admission. Changes in NIHSS, Glasgow coma scale, and modified Rankin scale were studied. Restocetin induced platelet aggregation (RIPA) was assessed by optical aggregometry (BIOLA LA230-2 AGGRWB) in modification by G. Born and Z. Gabbasov. von Willebrand factor (vWF) activity was examined as described by J. Olson. Results. RIPA was significantly higher in acute ICH compared to chronic ICH, AH and reference values. RIPA values were negatively correlated with hematoma volume and midline shift (r≥ –0.308, p≤0.035). vWF activity was significantly higher in ICH patients than in AH and reference values. Patients with AH also had significantly higher vWF activity than reference values. In acute ICH, vWF activity steadily increased reaching maximal values by 13—15th day. In chronic ICH, vWF activity decreased compared to the acute phase, but still remained higher than in AH patients or reference values. In acute phase, 1% increment in vWF values resulted in 0.5% increase in the risk of death during the follow-up period (95% CI 1.001—1.008, p=0.007). Conclusion. Endothelial dysfunction assessed by vWF activity increases during the acute hemispheric ICH and remains elevated in the chronic stage. vWF activity may be used as a marker in assessing stroke outcome and prognosis.