The author carried out a comparative analysis of the current business environment and investment attractiveness in the countries of the Customs Union and Common Economic Space on the background of the far-abroad countries. The article presents investigations dedicated to this problem conducted by various authoritative international expert organizations such as World Bank Group, Global Financial Integrity, Transparency International, UNCTAD, Ernst &Young, Forbes, etc. The article describes global trends in the investment policy and amounts of direct foreign investment, addresses the problems of illegal capital outflow from the countries of the Customs Union and Common Economic Space in general comparison with other countries around the world. The author pays attention to the problems and prospects concerning free economic zones of Belarus, Russia and Kazakhstan. The author stresses particular importance of harmonizing business environment within the territory of Common Economic Space. The article reveals that similar crucial systemic reforms are required for all three countries to change the investment climate greatly in the Customs Union and Common Economic Space. Due to the generalized international experience and on the basis of investigations and recommendations of authoritative global expert centers, the fundamental directions in solving current tasks and problems of this subject-matter are defined to improve the investment environment in countries of the Customs Union and Common Economic Space