Economic integration affects economic development through two main channels: growth and localization of the economic activities. The theories of endogenous growth and economic geography enable us to understand these mechanisms. We study in this paper their similarities and specificities before suggesting their useful combination within a single model. Indeed, both theories are based on the same Spence-Dixit-Stiglitz monopolistic competition framework. However, they suggest two different approaches to deal with the impact of economic integration. We consider that a third path, by proposing a synthetic approach, better answers the issues raised in terms of economic convergence and divergence by these two sets of models.