So far, only little is known about the impact of stroke on Event Related Potentials. The aim of this prospective study was to follow-up P300 latencies and choice reaction time in stroke patients and evaluate their changes over a prospective 1-year follow-up period.The study included 60 patients (mean age 57.1±7.2years, range 45–72years) with acute first-ever brain infarction. The control group consisted of 30 age-and sex-matched healthy volunteers (mean age 56.2±6.3years, range 42–72years). We recorded the P300 wave using an auditory oddball paradigm.The P300 latencies in stroke patients were significantly longer (Fz 423.5±37.6 Cz 429.9±40.6 Pz 433.8±35.0) than those of the control group (Fz 359.5±34.7 Cz 363.4±33.1 Pz 367.4±35.0). The latency of P300 showed a highly significant average improvement 12months after the stroke compared to the baseline.The reaction time was significantly longer in stroke patients than those of the control group.The P3 latency stands out as a marker for cognitive function recovery after the stroke.