What are the potential gains to the members of the Eurasian Economic Union (EAEU) of successful deep integration through the reduction of time in trade costs, the reduction of non-tariff barriers in goods and the liberalization of barriers against foreign suppliers of services? We estimate that if the EAEU were to effectively implement its objectives for trade cost reduction, it would lead to welfare gains as a percent of consumption of 0.8% for Russia, 1.7% for Kazakhstan, 3.1% for Armenia and 4.8% for Belarus. If these deep integration measures were partially extended to third countries, the welfare gains would increase to 3.6% for Russia, 4.5% for Armenia, 6.3% for Kazakhstan and 7.2% for Belarus. We estimate that the right to legally work in the Russian Federation for Armenians is approximately of equal value to Armenia as the combined aspects of the reduction of trade costs, including spillovers. We identify the external region and reforms that are most important for each member country regarding reforms and spillovers; this may inform lobbying positions of the member governments. Our innovative model, that includes imperfect competition and foreign direct investment, produces important differences compared with a perfect competition model.