Since the entry into force of Article 168a of the Code of Criminal Procedure
(i.e. 15.04.2016) the Polish courts have been faced with the need to find an answer to the question of how to proceed with evidence whose legality may be questioned. The content of this provision clearly indicates (in principle and briefly speaking) that in the process of making factual findings the courts (and other bodies involved in the procedure) should use prima facie illegal evidence, i.e. evidence obtained in violation of the law or used in a manner contrary to the provisions of law. The introduction of this provision into the system of criminal procedure made the system of evidence proceedings - rather rudimentary and unclear from the outset - even more vague and internally inconsistent. This article presents an analysis of the model of Polish evidence law in terms of the elements of the mechanism of excluding undesirable evidence from the trial. Such elements include: the manner in which evidence is adduced in the trial; the stage of assessing the admissibility of evidence; the moment when inadmissibility becomes apparent, and finally the model of the adopted procedure of deciding on the admissibility of evidence. It is important to establish not only why the evidence is considered inadmissible (from the point of view of its illegality), but above all how, i.e. in what procedure, such a decision is taken. The result of this analysis must have inevitably been postulates of legislative amendments, indicating the changes that are necessary in order to create a functional model of the mechanism for assessing the admissibility of evidence.