Abstract: This article examines whether international investors benefit from adding real estate investment trusts (REITs) to a mixed asset portfolio consisting of global stocks, bonds, hedge funds, and commodities. Previous literature has shown that REITs provide a strong co-movement with direct real estate in the long run. We therefore test the diversification potential of international REITs within the strategic asset allocation. Using the Johansen cointegration technique, we show that there is no long-term co-movement between REITs and the other asset classes in the period from January 1990 to December 2009. Thus, the empirical evidence suggests that REITs improve the diversification potential for active investors and those with a long-term investment horizon by simultaneously generating continuous cash flows.