The paper deals with the impact of informal institutions on the definition of the vector integration processes and the development of integration processes in the countries of the Customs Union and Ukraine. The degree of scientific development of the phenomenon in different economic schools is determined in this article. Economic mentality is a basic informal institutions, which determines the degree of effectiveness of the integration processes. This paper examines the nature, characteristics and effects of economic mentality on the economic activities of people. Ethnometrichal method allows to quantify the economic mentality that enables deeper understanding and analysis of the formation and functioning of political and economic system, especially business and management, establishing contacts with other cultures. It was measured modern Belarusian economic mentality based on international methodology Hofstede and compared with the economic mentality of Russia, Ukraine and Kazakhstan. With the help of cluster analysis congruence economic mentality of the Customs Union and Ukraine was determined. Economic mentality of these countries was also compared with the economic mentality of other countries in order to identify the main types of economic culture.