This study aimed at an analysis of the release of Braintype and Heart-type Fatty Acid- Binding Proteins (B-FABP and HFABP) in acute ischaemic stroke and their potential value as neurobiochemical markers of brain damage. We investigated 42 consecutive patients admitted within 6 hours after ischaemic stroke. Serial venous blood samples were taken hourly between 1 to 6 hours, and at 12, 18, 24, 48, 72, 96, and 120 hours after stroke onset. In all patients lesion topography was assessed and infarct volume was calculated. The neurological deficit was quantified by the National Institutes of Health stroke scale score, and functional outcome was assessed with the modified Rankin Scale 3 months after stroke. H-FABP and B-FABP concentrations showed peak values already 2 to 3 hours after stroke onset and remained elevated up to last measurements at 120 hours.Unlike BFABP, early H-FABP concentrations were significantly associated with the severity of the neurological deficit and the functional outcome. High H-FABP release was associated with large infarction on CT. Our study shows for the first time quantitative data of serum BFABP and H-FABP being elevated early in acute ischaemic stroke indicating that especially H-FABP might have the potential to be a rapid marker of brain damage and clinical severity. As both FABPs indicate damage to neuronal and glial tissue but are not specific for cerebral infarction, further investigations are needed to better understand the prolonged release of both in ischaemic stroke which is in contrast to the transient increase after myocardial infarction and can not be explained by their renal extraction.