This article is devoted to the background and history of the functioning of the Eurasian Economic Commission in the post-Soviet space. It examines the activities of its predecessor, the Customs Union Commission, which operated until November 2011, when, on the basis of the treaty “On the Eurasian Economic Commission,” its powers were transferred to the supranational body of the Eurasian Economic Community—the Eurasian Economic Commission. The Commission of the Customs Union was designed to facilitate the completion of the formation of the legal framework of the Customs Union of members of the Commonwealth of Independent States, including the Customs Code of the Customs Union. The main activities of the Eurasian Economic Commission from the moment of its creation to the present time are traced, and the main stages of the work of the Eurasian Economic Commission of all three convocations of its Boards are examined. The relationship of this supranational body of the Eurasian Economic Community and the Eurasian Economic Union with foreign partners is explored; and the conclusion of agreements on free trade zones with a number of states and regional associations, as well as achievements and challenges faced by integration processes in the Eurasian Economic Union space in the field of trade, customs procedures, technical regulations, industrial cooperation, digitalization of all spheres of activity, etc., is considered.