The subject. This paper deals with problems related to tax law with a special focus on legalregulation of the tax procedure contained in the Czech Tax Procedure Code. Attention ispaid in particular to tax penalty payments and the “non bis in idem” principle.The purpose to identify ratio between penalty payments in tax procedure and in criminalprocedure in context of “non bis in idem” principle.The methodological basis of the article is analysis of legislation and court practice of Czechrepublic, Austria, European Union, including formal legal analysis, comparative analysis,synthesis, systematic approach.The results and scope of application. The existing case law of the Czech criminal courts andof the Supreme Court was based on the legal opinion that a penalty payment imposed bythe tax administration in a tax procedure constitutes no punishment, i.e. it is no sanction ofcriminal nature, so that even the final (enforceable) decision of the tax administration doesnot create a “ne bis in idem”1 barrier in relation to criminal sanctions for the same taxesrelatednon-compliant action (tax evasion) in respect of the penalty payment imposed bythe tax administration.Conclusions. It would probably be advisable for the legislation to amend the relevant provisionsof the Tax Procedure Code in a way that the tax authorities concentrate within thelimits of their powers on proper tax collection and that the law enforcement authorities areauthorized to punishments for deliberate tax evasion. A suggested amendment may thereforebe the removal of the penalty payments from the Tax Procedure Code as the defaultinterest itself is sufficient instrument enough to penalize the taxpayers. Another option is to keep the tax penalty payment in the Tax Procedure Code, but its imposition would only be considered after making sure that the result of any criminal proceedings does not constitute a “ne bis in idem” prohibition within the meaning of Art. 40 (5) of the Charter and Art. 4 (1) of the Protocol No. 7 to the Convention, Section 11 (1) f), g), h), (2) and Section 11a of the Code of Criminal Procedure.