The article examines the activities of the Interparliamentary Assembly of the member states of the Commonwealth of Independent States in the field of forming a single legal space on the territory of the Commonwealth of Independent States. The authors pay attention to the mechanism of model lawmaking of the Interparliamentary Assembly of the Commonwealth of Independent States and the results of interparliamentary cooperation based on the results of 32 years of the Assembly's work. The creation of a unified legal space is assessed in the context of the degree of convergence of the national legislations of the member countries of the Commonwealth of Independent States, through the development and implementation of model normative legal acts in their legislation. The positive impact of the joint legislative process within the framework of the Interparliamentary Assembly of the Commonwealth of Independent States on the intensification of international contacts of expert communities is stated. The positive impact of the harmonization of the legal systems of the Commonwealth states on their cross–border interaction is noted – administrative barriers to trade, educational and cultural interaction are leveled. The role of the Interparliamentary Assembly of the Commonwealth of Independent States is defined as a unique instrument for the formation and legislative provision of a unified legal framework for the Commonwealth countries.