Asset pricing models have been used extensively in the recent real estate literature to evaluate real estate performance and estimate required rates of return of properties. In this paper, we show that the CAPM and its variants will derive a biased result when short sales are not allowed in the market. This problem is particularly serious for Asian property markets where investors are not able to short sell real estate indexes as a substitute for short selling real properties. We also demonstrate that the bias resulting from the short-sale constraint is related to the supply-and-demand conditions in the local market.