The Customs Union (CU) and the Eurasian Economic Union (EAEU) are an effective mechanism for protecting the domestic market, because the member states of these organizations follow a coordinated foreign trade policy. Conditions are being created for the development of the non-primary sector in these countries so as to modernize, diversify and enhance the competitiveness of their economies. For the countries of the EAEU, whose members are Russia, Belarus, Kazakhstan, Kyrgyzstan and Armenia, the development of small and medium-sized enterprises (SMEs) is highly relevant, especially considering the recession and Western economic sanctions against Russia, the largest EAEU economy. At the same time, their development encounters significant difficulties. This article examines the current situation and development trends in Kazakhstan’s small and medium business since the establishment of the Customs Union of Russia, Belarus and Kazakhstan in 2010 and the Eurasian Economic Union on 1 January, 2015. It shows the areas of government support for SMEs and argues the need for the development of a common strategy to regulate small and medium business in the EAEU space. In the functioning of the Kazakhstan economy as part of the Customs Union and the EAEU, the authors have identified problems caused by inadequate interaction between business and government. © 2017, CA and CC Press AB. All rights reserved.