Diabetes mellitus is associated with an increased incidence of ischaemic stroke but it is not established whether it may exacerbate its clinical course and prognosis. In the study we have assessed relations of fasting (1st-2nd day of illness) and pre-stroke glycaemia (measured as HbA1 and FA) with recent clinical manifestation and outcome within one month in 22 diabetics and 37 non-diabetics with ischaemic brain infarction in the internal carotid territory. Merely enhanced HbA1 in the majority of non-diabetic stroke patients confirmed impaired pre-stroke glucose tolerance but did not influence severity of hemiparesis and further prognosis. Abnormally high both HbA1 and dFA in diabetics, reflecting non-sufficient metabolic control of illness did not exacerbate acute manifestation of stroke and outcome. Fasting post-stroke glycaemia that expresses a stress response of brain origin was determinative for clinical state but not for one-month prognosis in diabetics and non-diabetics with brain infarction.