Main purpose of this thesis is to study the effect of infrastructural variables on Iran 's economic growth. A Cobb-Douglas production function is applied using labor and capital as two inputs. To find the effect of infrastructure, the economic indicators such as power and energy, traortation, communication, hygiene and health are used. Applying a yearly data of 1974 to 2001 and regression analysis, it is found that all four infrastructural variables are affecting the economic growth in the long run as well as in the short run. However, their effects are ordered as power and energy, traortation, hygiene and health, and communication