This review explores the main contributions to New Economic Geography (NEG) with a particular focus on the effects of economic integration on spatial development. Firstly, the theoretical framework is explored by presenting the fundamental building blocks of NEG and successively looking at the principal models of NEG. Then, empirical research within a NEG framework is summarised. Mostly, relevant empirical studies are surveyed to give a sense about the main paths that research has covered so far and, more particularly, the debate about the economic integration effect of the EU enlargement to Central Eastern European Countries (CEECs) is explored.