"The real estate market is rather new sphere of activity in Belarus. In spite of that there is interesting experience in urban land mass valuation field in Belarus. A comparison have been developed among different mass appraisal methodologies in an undeveloped property market. Recentely, a cadastral register was created in Belarus in 2004. This office should value land and buildings located in more than 208 cities and 24000 rural towns. It was also done mass appraisal of housing market of Minsk. In order to carry on this was used database included thousands objects and different methods and techniques (multiple regression analysis, rough set theory, neural network methods). The final results show how the choice of a mass appraisal methodology may be influenced by the ""efficiency"" of a property market (d'Amato,2005). "