Abstract
Land and mortgage registers constitute one of the basic elements of the system of real estate ownership protection. The article is an attempt to look at the regulations concerning the Polish land and mortgage register system from the viewpoint of our Constitution. Basically, as an instrument of protection of ownership and other rights land and mortgage registers realize in practice the principles of our Constitution, though certain solutions may arouse doubts as to their compliance with the basic law. The authors analyze one by one the issues relating to the principle of certainty of legal transactions, constitutional protection of ownership, protection of privacy and certain solutions in the area of land and mortgage register proceedings.