The study deals with the ascertainment of the highest and best use in the valuation of a mixed‐use development site in the context of Singapore where the introduction of ‘white sites,’ which gives the developer maximum flexibility on the best mix of permitted uses, have made the valuation of such sites intriguing. Valuers in Singapore rely on the Residual method to value ‘white sites’ because of the dearth of sales data. It is argued that the usefulness of the residual method may be severely compromised, as the method cannot resolve the optimization problem on which the highest and best use or mix of uses of such sites depends. The study theoretically and empirically demonstrates that a combination of linear programming and the Residual method would provide a well‐ researched and scientifically supported estimate of value.