EU-TE trade is increasingly characterized by intra-industry trade. For some countries (Czech Republic), the share of intra-industry trade in total trade with the EU approaches 60 percent. The decomposition of intra-industry trade into horizontal and vertical shares reveals overwhelming vertical structures with strong quality advantages for the EU and shrinking quality advantages for TE countries wherever trade has been liberalized. Empirical research on factors determining this structure in an EU-TE framework has lagged theoretical and empirical research on horizontal trade and vertical trade in other regions of the world. The main objective of this paper is, therefore, to contribute to the ongoing debate over EU-TE trade structures, by offering an explanation of intra-industry trade. We utilize a cross-country approach in which relative wage differences and country size play a leading role. In addition, as implied by a model of the product-quality cycle, we examine income distribution factors as determinates of the emerging EU-TE structure of trade flows. Using OLS regressions, we find first, that relative differences in wages (per capita income) and country size explain intra-industry trade, when trade is vertical and completely liberalized and second, that cross country differences in income distribution play no explanatory role. We conclude that if increasing wage differences resulted from an increasing productivity gap between high-quality and low-quality industries, then vertical structures will, over the long-term create significant barriers for the increase in TE incomes and lowering EU-TE income differentials.