This paper explores the East-West dichotomy of outsourcing in the European Union in the context of its 2004 eastward enlargement. The purpose of the study is to shed light on the connection between outsourcing and the causal logic of regional integration. The conventional view is that the transfer of business operations from Western Europe to low-cost locations to the east represents a process of outsourcing West-European jobs which deprives the EU core of growth opportunities to the exclusive benefit of the new members from Eastern Europe. This analysis posits the systemic functions of EU outsourcing as a mechanism of economic homogenization in the regional market along its three principal dimensions: investment, commodity trade, and labor mobility. At the macro-level, outsourcing complements capital movements and trade, and acts as a substitute for labor mobility. Keeping labor mobility “down” is the main value added of EU outsourcing. Empirically, its relevance to the regional market is established in an input-output framework of relationships with indicators of economic convergence (homogenization effects) and labor mobility (substitution effects) in the EU. Positive correlations with indices of business synchronization and weak negative correlations with measures of labor supply and wages suggest that outsourcing fits well both with strategies fostering market integration and those counterbalancing the politically sensitive labor mobility in the EU. There is no significant evidence to suggest that, at the aggregate level, outsourcing has independent substitution effects with regard to unemployment rates and wages in Western Europe. The geographic expansion of EU integration, therefore, is not a proxy for losses of social welfare in the West. The paper concludes that as the cost efficiency and resource allocation functions of outsourcing facilitate the homogenizing dynamics of regional integration, it is likely to become increasingly subsumed under EU-level regulation and monitoring in a trade-off between the regional interest and domestic sectoral concerns.