Abstract: In this article the authors discuss particular problems that relate to the reformation of the criminal procedure law in the CIS countries including the new version of the Criminal Procedure Code issued in Kazakhstan (2015) and Kyrgystan (2017), as well as obstacles that may prevent from implementation of a number of criminal law provisions. For this purpose, the authors define distinctive features of the criminal procedure law in terms of ongoing legal reforms in the CIS countries. They focus on the most troublesome criminal procedure institutions that may render a significant influence on criminal procedure in general. The article contains comparative law analysis of a number of provisions of the criminal procedure law in the CIS countries including new versions of the Criminal Procedure Codes. The authors of the article also provide a review of the new ideology followed by the legislator whch is proved by the principles set forth by the Criminal Procedure Codes of the CIS countries. The authors pay special attention to such important principle as adversarial system in a criminal trial but at the same time cover factors that, according to the authors, prevent from full implementation of that principle. They also give recommendations of the legislative nature that, to some degree, may help to achieve the tasks and objectives set forth for this sphere. The authors also raise questions about differentiation of criminal procedure stages and implementation of the institution of unofficial (special) investigative actions based on the provisions of the Criminal Procedure Codes of some CIS countries. Thus, the themes brought forth by the authors in terms of criminal procedure reforms, create conditions for the review of some provisions of the Criminal Procedure Code and making amendments and changes to the legal acts that ensure successfull realization of some institutions mentioned in the law.