The paper investigated the relationship between financial sector development and economic growth in Nigeria for the period 1980-2009. Functional monetary policy measure was used to empirically determine the long run relationship of private investment and economic growth in Nigeria. Appling Vector Auto-Regression Model technique to test the stationary series of variables and the result showed that money supply has a negative but GDP and Others have positive significant impact on private investment in Nigeria in the short run but the variables became statistically significant in the long run. This implies that the monetary policy in Nigeria has positively affected the growth of private investment in the Nigeria economy.Key Words: Private Investment, Monetary Policy, Co-Integration, Vector Auto-Regression, Granger, Johansen Test.