Fiscal policy has much controversial debate regarding its effectiveness on economic growth. Taxation and government expenditure are two main instruments of fiscal policy. This paper is aimed to analyze the effect of different categories of government expenditure on economic growth of Pakistan. Based on impact on economic growth, government expenditures are classified into productive (having positive or neutral effect on economic growth) and unproductive expenditures (having negative or insignificant impact on economic growth). The data time span for this study is 1979-2012. After classification of expenditures, the impact of fiscal instruments is analyzed by utilizing the ARDL approach of Co integration which is a better estimation technique for small sample size. The results reveal that unproductive government expenditure have negative impact while productive government expenditure has insignificant impact on the economic growth. It is found that private investment positively and significantly affect the economic growth. On the other side, direct and indirect taxes have also insignificant impact on economic growth of Pakistan