In the process of defining the highest and best land use is vital that the purpose of the land and spatial implementation conditions are clearly defined. The land use within spatial plans should be defined using professional bases, taking into account principles of sustainable development, quality of living conditions, spatially coordinated and complementary sorted activities, environmental protection program and other factors. Based on written above, a rational investor building for sale on the market, will start the construction on certain land only, if the net present value of the project is higher than zero. The thesis deals with the case of an investor who has to decide between several types of housing construction on the building plot, located in the City municipality of Ljubljana, in accordance with the principle of the highest and best land use.