Day fines were implemented into the Czech Republic criminal system in 2010. They shall reflect the gravity of the crime and personal and financial circumstances of the offender. For natural persons, the daily fine shall be based on an average daily income and for legal persons on their overall financial situation. Day fines are, together with the sanction of prohibition of an activity, one of the two most popular sanctions for legal persons and they are used for various crimes. On the contrary, natural persons are sanctioned with day fines in less than five per cent of cases and the fines are used mainly as a sanction for the crime of hazard due to intoxication (including some events of drunken driving), which represents more than half of the occasions when day fines were imposed. The courts’ practice is, however, somewhat detached from the theoretical underpinnings of the concept of day fines as it appears that judges in reality first set the overall amount of the fine they want to impose and then (without any clear system) divide it into the daily fine unit and the number of days. In most cases the total amount of the fine does not seem proportionate to the offender’s income.