OBJECTIVES The purpose of our study was to observe whether a seasonal change or weekly variation can be shown in the incidence of an acute myocardial infarction (AMI) and a transient ischemic attack (TIA) during a three-year study period in Hungary. We also examined whether the occurrence of an AMI or a TIA is influenced by age and sex. METHODS We have analyzed AMI (N=51,802) and TIA (N=12,592) patients received at clinics and hospitals in Hungary between 2005 and 2007. Data were collected from the database of the National Social Security Fund (OEP) based on the International Classification of Diseases (ICD codes). RESULTS Based on our results, a weekly and a seasonal variation can be seen in the onset of a transient ischemic attack and an acute myocardial infarction. With regard to seasonal variation, there was a significant difference between the number of events for each season (p<0.01), and the peek period of AMI and TIA was found during the months of spring, the lowest number of events of AMI is during the summer and in the case of TIA is in autumn. In case of sexes, difference was only found in the seasonal variation of number of events of AMI (p<0.01). The weekly peek period of infarction and cerebral circulatory disturbance was found on the first day of the week, on Monday, with a gradually decreasing tendency towards the end of the week. Examination of variation according to age groups showed a significant difference only in case of TIA with consideration to daily variation. CONCLUSIONS The decrease is higher from Friday to Sunday. In summary, the results of our study show that the incidence of an acute myocardial infarction and a transient ischemic attack shows characteristic variation with regard to seasons and the days of the week.