The aim of this study was to evaluate the prognostic value of heart rate variability in patients with acute myocardial infarction (AMI) treated with thrombolysis. 90 consecutive patients with AMI were enrolled in the study. From 24-hour ECG recordings obtained at discharge and after 6 months of follow-up we measured several time-domain indexes of HRV: SDNN, SDANNI, rMSDD and pNN50. During 30 months of follow-up (1-60) we noted 12 cardiac events (sudden death, unstable angina demanding hospitalization or acute myocardial infarction). The mean HRV values in event group were lower than in group without events at discharge and after 6 months but these differences were statistically significant only after 6 months. We concluded that time-domain indexes of KRV: SDNN and SDANNI had prognostic value 6 months after AMI.