According to the original wording of the Regulation on the register of land and buildings of 2001, in the real estate cadastre there was one attribute associated with the use of a building structure - its intended use, which was applicable until the amendment to the Regulation was introduced in 2013. Then, additional attributes were added, i.e. the type of the building according to the Classification of Fixed Assets (KST), the class of the building according to the Polish Classification of Types of Constructions (PKOB) and, at the same time, the main functional use and other functions of the building remained in the Regulation as well. The record data on buildings are captured for the real estate cadastre from other data sets, for example those maintained by architectural and construction authorities. At the same time, the data contained in the cadastre, after they have been entered or changed in the database, are transferred to other registers, such as tax records, or land and mortgage court registers. This study is the result of the analysis of the laws applicable to the specific units and registers. A list of discrepancies in the attributes occurring in the different registers was prepared. The practical part of the study paid particular attention to the legal bases and procedures for entering the function of a building in the real estate cadastre, which is extremely significant, as it is the attribute determining the property tax basis.