The convergence hypothesis is very attractive idea from an economic and social point of view, hence it is not surprising that interest in research on this topic has not subside for a decades. Determinants of convergence appear both on the supply and the demand side of the economy. Those determinants are numerous and comes in a forms of human and physical capital and also in their different interactive byproducts. The focus of this research is to examine the convergence process of European Union regions regarding their sectoral specialization. After reviewing the relevant theoretical and empirical achievements, the methodological framework has been done to empirically verify the main hypothesis according to which the real convergence process of European Union regions is determined by their specialization structure. The main working hypothesis is elaborated on four supplementary hypotheses that are set to empirical testing on the data for 247 European Union NUTS II regions in the 14-year period from 2000 to 2013. The first supplementary hypothesis confirmed that specialization of European Union affects the regions level of productivity. Further analysis confirmed the second supplementary hypothesis, according to which the differences in productivity between regions arise from differences in productivity between sectors of their specialization. Finally, the third and fourth supplementary hypotheses have been tested to examine the partial influence of certain sectors of specialization on economic growth. In particular, the third supplementary hypothesis confirmed that the regions specialized in financial and business services, and in other high value added sectors achieves higher growth rates compared to other regions. On the other hand, the agricultural sector has demonstrated a lower productivity and consequently a negative impact on growth, resulting with confirmation of the fourth supplementary hypothesis. Overall, the cross-examination of supplementary hypotheses confirmed the main hypothesis, which implies a general conclusion that the real convergence of European Union regions is affected by theirs sectoral specialization.