The former Soviet Union Republics striving to integrate have created several integration organizations during the past 30 years - the Economic Union, the Free Trade Zone, the Custom Union, the Eurasian Economic Community and the Eurasian Economic Union. The Councils of the Heads of State and the Councils of the Heads of Government have always been among the organs of the organizations with as a rule a commission provided specially to act not on behalf of the member states, but on behalf of the organization itself and empowered to take decisions of compulsory character for the member states. The analysis shows that the succession in the integration organizations is similar to those in other international organizations. Though there is no single normative act providing for the succession of international organizations several regularities are of relevance. The succession in international organizations is performed not by the organizations themselves, but by the member states; the basis for the succession is not territory as during the state succession, but the transfer of functions from the predecessor organization to the successor. Integration organizations created in the post-Soviet territory possess different identity, they do not continue one another, they are separate subjects of international law and they implement their own succession through member states. The Commission of the Customs Union is of special interest. Its personality ceased to exist in 2014 due to the creation of the Eurasian economic commission of the EAEU. The succession of the predecessor to the successor commissions is implemented concerning the three parts: the Commission itself, its functions and its decisions. The Commission is abolished, its functions are inherited by the Eurasian Economic Commission and the decisions have been implemented in the national legislation of the member states, and in the norms and rules of the acts adopted by the Customs Union and the Eurasian Economic Union. The decisions of the Commission continue to act as far as they do not contradict the EAEU Treaty. The general legal basis of the EAEU is not the same as existed within the Customs Union and if contradictions arise, it must be changed since the basic norms of the new legal order have been altered.