Numerous studies have reported the weekly variation of an acute myocardial infarction. The Monday peek has been connected with higher rate of physical and mental, work-related stress. We wished to study the weekly variation of an acute myocardial infarction (AMI) in the group of workers and pensioners, and to find out whether National Holidays on the first day of the week could influence the weekly rhythm of an acute myocardial infarction. We carried out the retrospective analysis of patients admitted to Hungarian hospitals with the diagnose of an AMI (n=90,187) between 2002 and 2007. According to the morbidity data of an AMI, the weekly peek was detected on the first work-day of the week, showing a gradually decreasing tendency until the end of the week. Morbidity rates on Mondays being National Holidays were similar to the number of events on Saturdays and Sundays (Z=−24,431; p<0.001). There was a significant difference between the number of events on work-days and weekends (Z=−27,321; p<0.001). No marked difference was found between workers under the age of 65 and pensioners above the age of 65, or between the two sexes. The results of our study reveal that the occurrence of an AMI shows characteristic changes throughout the days of the week, and the first work-days of the week may be related to higher incidence of an acute myocardial infarction.