This research work investigates the role and the impact of foreign direct investment on economic growth, and mainly developing countries were chosen, as FDI has the more effect on developing countries than on developed ones.In order to explore it , two methods were applied such as Cobb-Douglas production function and dynamic regression with Generalized Mean Method (GMM).The data for countries was used particularly from World Bank Data and Penn world tables database.In conclusion it became clear that the hypothesis has partly been proved.It was confirmed that the influence of FDI inflow on economic growth has a positive character, the FDI outflow negatively correlated to labor productivity.