The study represents an assessment of socioeconomic integration consequences within the framework of the Eurasian Economic Union (EEU) for the participating countries-Armenia, Belarus, Kazakhstan, Kyrgyzstan and Russia. The authors implemented a personally developed approach of integral efficiency evaluation based on the calculation of the coefficients of state social and economic development indicators of growth as a main method for such assessment. These indicators allow us to characterise the following segments: national welfare, inflation, investment activity, labour market and the level of poverty, and the condition of the main economic sectors. The authors determined that Russia is the only export-oriented member of the Eurasian Economic Union (EEU). The worst consequences of integration in the cross-border trade sphere are observed in Belarus. For the analysed countries (excluding Kyrgyzstan), the first year of the existence of the EEU can be characterised as a period of economic recession (2015). According to the comparison of integral rates for the periods of 2005-2014 and 2015-2017, it was defined that the integration had a positive economic effect in the short term. By now, all the five participating countries have achieved the same level of social and economic development as in the pre-crisis period (2012-2013). In terms of the EEU membership, the calculated economic growth expands from 3% in Kyrgyzstan (by the integral index) up to 30% in the Republic of Belarus. Russia has also significantly strengthened its position (the growth rate of the index in 2015-17 was 25%).