The objective of this PhD is to determine the main conditions under which attractive FDI policies of developing countries can impact their growth level. The theoretical framework belongs to the new endogenous growth models. The empirical framework is the case of Tunisia during the period 1970-2009. We consider a model of six simultaneous equations reflecting the growth of the Tunisian economy. First, this model assesses the impact of FDI on the growth process and permits us to establish the necessary conditions which ensure positive effects of spillovers. Second, we define the determinants of FDI located in Tunisia.In particular, we exhibit the need for Tunisia to develop technological capabilities and human capital resources that affect the conditions to assimilate knowledge’s and technologies from outside. We also highlight the importance of some other factors including the business environment in the host country. These factors ensure that spillovers are efficient transmission channels in order to obtain sustained growth. The developing countries should therefore focus their efforts on improving the attraction of FDI policies and their absorption capacity with the view to create a more favourable environment for their development.