Criminal proceeding in the Republic of Croatia is regulated by the Criminal procedure Code and it is initiated, conducted and terminated by applying exclusively rules prescribed by Criminal procedure Code. The rules of this Act guarantee that an innocent person shall not be convicted and punished for a criminal offence in a proceeding before the competent court and under the conditions stipulated by law. In criminal proceeding illegal evidence are a problem and in criminal law theory they stand as one of most complex issue which causes a large number of debates and disputes that point to complexity of the problem of illegal evidence. Illegal evidence is evidence obtained in a way representing a violation of the prohibition of torture, cruel or inhuman treatment guaranteed by the Constitution, domestic law or international law, obtained in a way representing a violation of fundamental human rights to defence, dignity, reputation, honour and inviolability of private and family life, guaranteed by the Constitution, domestic law and international law, obtained in a way representing a violation of criminal procedure provisions expressly provided in this Act,and last, obtained through illegal evidence. In the Republic of Croatia, The court decisions may not be founded on evidence obtained in an illegal way.