On August 16, 2006 in Sochi, the presidents of EurAsEC member states adopted Resolution No.313 on the formation of the three-state (Belarus, Kazakhstan, Russia)  Customs Union  within the EurAsEC.

The legal framework for the Customs Union was established to accommodate a transition from the first stage of the already functioning free trade regime to the second stage of the three-state Customs Union, to ultimately be joined by other EurAsEC countries at any time.

On October 6, 2007, documents were signed establishing the institutional structure of the Customs Union and determining the mechanisms for accession of non-member states. The 2007-2010 action plan for the formation of Customs Union was also implemented.   A regular meeting of the EurAsEC Interstate Council was held on October 10, 2008 in Bishkek among heads of state. Changes were introduced to the statute and procedures. The EurAsEC Interstate Council at the level of heads of state assumed the functions of the supreme body of the Customs Union.

An important step in the establishment of the three-state Customs Union was a meeting of the EurAsEC Interstate Council held on June 9, 2009 in Moscow, during which the prime ministers approved the draft of a unified customs tariff. At the summit, Russia, Belarus, and Kazakhstan agreed to join the World Trade Organisation as a single customs territory, and the Customs Union Commission was instructed to initiate the accession process.

The timeframe for the establishment of the Common Customs Territory of the Republic of Belarus, the Republic of Kazakhstan, and the Russian Federation were determined, and the preliminary phase was to begin January 1, 2010, followed by a first stage on July 1, 2010 and a second stage on July 1, 2011.

Another decisive step in the creation of the Customs Union was taken at a meeting of the EurAsEC Interstate Council on November 27, 2009 in Minsk, where presidents of the three states approved the decision to declare the Customs Union effective on January 1, 2010.  

Those present signed the 'Treaty on the Customs Union’s Customs Code' and drafted an action plan for the enforcement of the code. The Unified Customs Tariff was approved and enacted on January 1, 2010, as established by the supranational body of the Customs Union Commission. They also drafted the 'Unified Foreign Economic Activity Commodity Nomenclature' and other international documents aimed at the realisation of unified customs and tariff regulations. Members of the Customs Union also approved a statute on the Expert Council, an advisory body that will hold quasi-judicial hearings to consider appeals from commercial entities in relation to their activities within the Customs Union.  

At a meeting of the EurAsEC Interstate Council held on May 21, 2010 in St Petersburg, the prime ministers of member states made decisions on the enforcement of important international documents comprising the legal framework of the Customs Union.

The key result of the July 5, 2010 EurAsEC Interstate Council meeting in Astana was the adoption of the Customs Code of the three-state Customs Union scheduled to come into force on July 6, 2010 (in Russia and Kazakhstan, it came into force on July 1, 2010).

The first stage of the creation of the Customs Union within the EurAsEC was completed.

During a meeting of the EurAsEC Interstate Council, the supreme body of the Customs Union, on November 27, 2009 in Minsk, the presidents of Belarus, Kazakhstan, and Russia agreed to intensify their efforts to draft the legal framework for the Common Economic Space. By December 20, 2009, the Customs Union Commission was to draft and present an action plan for the establishment of the Common Economic Space to its respective heads of state On December 19, 2009, the EurAsEC Interstate Council, the supreme body of the Customs Union, adopted the action plan for the establishment of the Common Economic Space of Belarus, Kazakhstan, and Russia at the level of heads of state. The first package of 14 basic documents was to be signed by January 1, 2011 and enacted by July 1, 2011; the second package of six documents was to be signed by July 1, 2011 and enacted by January 1, 2012.

A decision to accelerate the process was then made at a meeting of the EurAsEC Interstate Council on July 5, 2010 at the level of heads of state. The governments of Belarus, Kazakhstan, and Russia were commissioned to take measures to ensure the ratification of all twenty international agreements comprising the legal framework of the CES by January 1, 2011. Some of the documents were later combined, so that the current package contains 17 documents.

At a meeting of the EurAsEC Interstate Council on November 19, 2009, the prime ministers of the Customs Union states signed 4 agreements.

The remaining international agreements comprising the legal framework of the CES were signed at a meeting of the EurAsEC Interstate Council on December 9, 2010 at the level of heads of state. Three documents were signed by heads of state, and 10 others were signed by deputy prime ministers. The process of preparing and signing relevant agreements was completed.

The agreement on the organisation, management, function, and development of common markets for petroleum and petroleum products among CES member states was to be enforced in parallel to bilateral agreements on Russian-Belarusian and Russian-Kazakh relations in the sphere of petroleum and petroleum products market. These agreements were also signed at the meeting.

The ratification of these agreements is to be finalized by July 1, 2011. All agreements are to come into effect by January 1, 2012, thereby initiating the full implementation of the Common Economic Space and the free movement of goods, services, capital, and labour.  

At the end of the summit, heads of state from member nations adopted a declaration assuring the effective development of the integration process in Eurasia, with Kyrgyzstan and Tajikistan soon to join the Customs Union and the CES, “so as to jointly follow a path of enhanced socio-economic integration.” The declaration also stated that the CES remains open to the accession of other nations.

According to the document, by developing the Customs Union and the Common Economic Space, member states are moving toward the creation of the Eurasian Economic Union, which would promote and guarantee balanced, complementary, and mutually beneficial economic cooperation among member nations, international economic organisations, and the European Union, resulting in the eventual creation of a common economic space.