['To conduct a pilot study to evaluate the blood levels of brain derived neurotrophic factor (BDNF), glial fibrillary acidic protein (GFAP), neuron specific enolase (NSE) and S-100B as prognostic markers for neurological outcome 6 months after hypothermia treatment following resuscitation from cardiac arrest.', 'Prospective observational study.', 'One intensive care unit at Uppsala University Hospital.', 'Thirty-one unconscious patients resuscitated after cardiac arrest.', 'None.', 'Unconscious patients after cardiac arrest with restoration of spontaneous circulation (ROSC) were treated with mild hypothermia to 32-34°C for 26h. Time from cardiac arrest to target temperature was measured. Blood samples were collected at intervals of 1-108h after ROSC. Neurological outcome was assessed with Glasgow-Pittsburgh cerebral performance category (CPC) scale at discharge from intensive care and again 6 months later, when 15/31 patients were alive, of whom 14 had a good outcome (CPC 1-2). Among the predictive biomarkers, S-100B at 24h after ROSC was the best, predicting poor outcome (CPC 3-5) with a sensitivity of 87% and a specificity of 100%. NSE at 96h after ROSC predicted poor outcome, with sensitivity of 57% and specificity of 93%. BDNF and GFAP levels did not predict outcome. The time from cardiac arrest to target temperature was shorter for those with poor outcome.'] Is s-100B superior to NSE , BDNF and GFAP in predicting outcome of resuscitation from cardiac arrest with hypothermia treatment?