The primary reason of this study is to test real interest rate and its impact on investment to the extent of Pakistan span from 1964 to 2012. To test the long-term nexus among level of income, interest rate and investment mainly Johansen Cointegration test is employed. The hypothesis of this study is that investment has an inverse association with real interest rate in Pakistan. If relationship exists then policy maker can make better policy for Pakistan. The outcomes confirm economic theory and a number of other studies that investment has significantly inverse association with real interest rate in Pakistan.