Abstract: The impact of agriculture in developing countries like Nepal are in top priority, moreover agriculture is used to create employment and to increase the national income and per capita income. This research paper examines casual-relationship between Gross Domestic Product of agriculture and Economic Active Population with reference to Nepal. The data were drawn from Ministry of Finance and Central Beauro of Statistics from 1983/84 to 2016/17 in macro level. It estimates the output of production function where R-square 0.990 means that 99 percent Gross Domestic Product of agriculture explained on the basis of economic active population and expenditure in agriculture sector of Nepal. So that, this is highly significant among them. Similarly to estimate the growth rate, where one percent increase in economic active population age (15 to 59) years leads to 0.630 percent increase in gross domestic product of agriculture in Nepal. Overall result shows that there has been significant impact of GDP of agriculture on macroeconomic variables.