All Praise be to Allah alone, the most Gracious, the most Merciful, and the prayers and peace be upon the one after whom there is no prophet. The study dealt "Proportionality of the Punishment to the Crime" and it aimed to clarify the essence and nature of this principle and the role of the constitutional judiciary in monitoring the regulator's discretionary power while assuming its regulatory functions. The study included three parts and a conclusion. Part one dealt with the Concept of proportionality between crime and the punishment, whereas part two discussed Individualization of punishment and its relationship to proportionality between crime and the punishment, and part three focused on the issue of Aggravating and mitigating circumstances and their relationship to the proportionality between punishment crime and the punishment. The researcher used the descriptive approach in analyzing the legal scholastic texts, and at the end of the study, the researcher concluded that the Saudi regulator stipulated the principle of proportionality between the crime and the prescribed punishment in a number of systems among them the system for disciplining employees, combating terrorism and money laundering. It was also concluded that the principle of proportionality within the scope of the constitutional system means two things: legislative proportionality which means compatibility between the internal elements or components of legislation (cause, place and purpose), and constitutional proportionality which means consistency between the legislative text and the constitutional text or principles derived from the constitution. The study also revealed that the principle of proportionality is part of the legislator's discretionary power, but the constitutional judiciary removed the legislator's discretionary power from the scope of its control, except for the principle of proportionality, which it subjected to its control.
