Throughout the last decades, the global economy has been completely sophisticated. It has evolved in an increasingly more and more complicated context, given the mechanism of free trade, free haw of capital and goods; investment has become important for developing countries. In this respect, it is necessary to study the impact of foreign direct investment (FDI) on the economic growth of the host country, especially in Tunisia. By using recent techniques of time series analysis over the period 1975-2009. Our empirical results thus suggest that FDI could help boost the process of long-term economic growth.