The Parliament acts as the primary subject of constitutionalization of the criminal law, ensuring the adoption of normative acts, which in their content reliably reflect and fully embody the norms and values of the country’s Constitution. This requires parliamentarians to work hard on a preliminary constitutional review of drafted and adopted criminal laws. At the same time, an analysis of the practice of legislative activity shows that such a check is either not carried out, or is carried out purely formally. In this regard, the issue of introducing into parliamentary practice the institution of compulsory legal examination of laws that affect the rights and freedoms of citizens is being actualized. Legal examination of criminal law bills requires that experts have deep and special legal knowledge in the field of constitutional and criminal law, criminology and criminal policy, international and humanitarian law. However, the legal examination of the draft law cannot be perceived as an unequivocal decision on its constitutionality.