This article analysis the effects that EU Eastern enlargement will have on the Spanish economy. As opposed to the widespread belief that the major impact on Spain will stem from the reduction of Community funds received, the impact on two real variables is also analyzed here, namely trade and foreign direct investment, and evidence is offered of the restructuring of economic activity in the enlarged Europe and its effects on the Spanish economy. In addition, the competition for Spain of the new partners in the Community market is also examined. One of the most noteworthy results is that the competition of the new members of the European market is becoming stronger, as they have a commercial structure that is becoming more and more similar to Spain's and with a greater technological content. This phenomenon appears to be the outcome of the activity of the multinationals, which are re-organizing their activity and transferring part of their production to Central Europe to capitalize on the cost advantages of the new members and their more strategic geographical situation. Furthermore, evidence is put forward that, if the criteria for eligibility for the Structural and Cohesion Funds are not altered, Spain will be one of the countries in which the budgetary situation will deteriorate most in the post-enlargement EU.