Abstract
This study is undertaken to determine the relative impacts of the uncertainty of macroeconomic variables on investment and make policy recommendations that may help dampen their fluctuations. In the study, generalized autoregressive conditional heteroscedasticity (GARCH) model was applied in the estimation of uncertainty of the macroeconomic variables. In the analysis of the data, econometric results were obtained from cointegration test and ordinary least squares. Thus, the study revealed the following: (1) existence of long run relationship between some of the macroeconomic variables and investment, (2) possibility of convergence of the variables from the short run to the long run with slow speed of adjustment and (3) the uncertainty of most of the macroeconomic variables impact negatively on investment in Nigeria. The study recommends the use of appropriate policy instruments that will bring about macroeconomic stability which provide conducive and enabling environment for private investment to thrive.