The subject of this paper is the rationalization of penalties imposed on the basis of petty offences law. The author briefly presents the directives and rules of imposing specified petty offences penalties and points out to the need to introduce changes in this area. The presented considerations lead to the conclusion that, in the face of the inevitable thorough amendments to the provisions of the petty offences code, the favorable solutions seem to be not only eliminating the basic arrest penalty and maintaining a substitute arrest penalty, but also eliminating the reprimand as the mildest penalty for petty offences. Moreover, the author indicates the necessity to increase the limits of the fine penalty and proposes a wider application of restriction of liberty penalty.