The purpose of this study is to examine the determinants of investment in the Nigeria economy making use of time series data for the period 1970-2003. The study employed the Ordinary Least Square (OLS) and the Cochrane Orcutt technique of estimation. The main conclusion which emerged from the analysis is that increase in investment will lead to an increase economic growth. The policy implication of this finding calls for the harmonization of interest rate policy, exchange rate, financial savings, inflation rate, and maintaining a stable macroeconomic environment and financial reforms to stimulate investment and capital accumulation. Also good governance is also important for sustainable economic growth.