Objectives:
The subject of this study is to present and to compare two institutions. The first of these is the active regret regulated in the Polish penal and fiscal law. The second of these is self-reporting normalized in the Roman law. The aim of the study is to present various methods of acquiring the possibility of increasing the income to the budget in Roman law under Polish law.

Material and methods:
The work will be based on the legal-dogmatic, descriptive and legal-comparative method. The latter method will allow us to compare active regret with the institution of self-apprehension.

Results:
Both institutions show far-reaching similarities, but also some differences. Hence, the simple assumption that the modern solution is the reception of the Roman solution cannot be accepted. However, the inspirations cannot be excluded. In this case, the solution from Roman law would be a kind of prototype of the modern institution of active regret

Conclusions:
Making the comparison, however, allows us to suggest some changes in Polish law that could increase the state budget, which is undoubtedly a vital interest of the state treasury.