This study assesses the level of implementation of Enterprise Risk Management (ERM) in companies listed in the Nairobi Stock Exchange (NSE). The study also seeks to test the significance of factors affecting this level of ERM implementation and to investigate whether the level of ERM implementation has a positive effect to the value of companies as measured by Tobin’s Q. Data was collected from a sample of 22 companies listed on the NSE for the periods ended December 2009. | The effect of enterprise risk management implementation on the value of companies listed on the Nairobi stock exchange