Introduction - The therapeutic time window of acute stroke is short. Decision on the use of intravenous thrombolysis is based on well-defined criteria. Any delay in the transport to a designated stroke centre decreases the odds of therapeutic success. In Hungary, the admission rate of stroke patients peaks on Monday, the number gradually decreasing by the end of the week. This phenomenon has long been suggested to be due to the lack of emergency care approach. According to the literature, however, returning to work following a holiday is a risk factor for acute stroke. A similar phenomenon is well-known in veterinary medicine, a condition in horses referred to as ‘Monday morning disease’. In our study, we analysed the distribution of admissions due to acute stroke by the day of the week in 4 independent data sources. Patients and methods - The number of patients admitted to the Szent János Hospital, Budapest, Hungary with stroke and that of emergency ambulance transports in the whole city of Budapest due to acute stroke were analysed in the period between January 1 and March 31, 2009. The distribution of thrombolytic interventions reflecting hospitalizations for hyperacute stroke was analysed based on data of the Szent János Hospital in 2009-2012, and on national data from 2006-2012. Descriptive statistics was used to present the data. The variation between daily admission was compared by chi-square test. Results - The proportion of daily admission of stroke patients admitted to the Szent János Hospital was the highest at the beginning of the week (18% on Monday, and 21% on Tuesday) and the lowest on the weekend (9% and 9% on Saturday and Sunday, respectively). The distribution of ambulance transports in Budapest due to acute stroke tended to be similar (15% and 15% on Monday and Tuesday, whereas 13% and 12% on Saturday and Sunday, respectively) on different days of the week. No such Monday peak could be observed in a single centre regarding thrombolytic interventions: 18% and 19% of the total of 80 thrombolytic interventions in the Szent János Hospital were performed on Monday and Sunday, respectively. At the national level the higher Monday rate is obvious: during a 7-year period 16.0%, 12.7%, and 13.5% of all thrombolytic interventions in Hungary were performed on Monday, Saturday and Sunday, respectively. Conclusion - Monday preference of stroke is not exclusively caused by the lack of emergency care approach, and the phenomenon is not consistent at the individual hospital level in cases undergoing thrombolysis.