The aim of this thesis is to define the position of an expert on an expropriating proceedings and creating an expert opinion for these uses. In the theoretical part the definitions connected to expropriation and expropriating proceedings are explained. An expert activity and an expert opinion are defined in other chapters in the theoretical part. Last two chapters deal with transportation infrastructure and evaluating of the immovable assets where there are the established price, the common price and the ways of evaluating. The practical part of the thesis is devoted to the expert opinion in expropriating proceedings. The established price, the standart price of expropriated immovable assests and compensation for moving are set in a comparing way within the expert opinion.