There are currently two basic public registers concerning real estate in Poland: the Land and Building Register (EGiB) and the Land and Mortgage Register (KW). The descriptive data in the Land and Building Register includes information on registered plots of land, buildings and premises, while the Land and Mortgage Register presents information on the legal status of the property. These systems operate independently, as they are maintained by different public administration bodies. However, the data contained in the Land and Building Register form the basis for the designation of the property in the Land and Mortgage Register, and thus both registers are interconnected and should contain consistent information. It is crucial that the information repetitively reported in both the EGiB and KW are identical. Consistency of data attribute values contained in both registers provides technical and organisational opportunities for harmonisation and integration of data from both sets. It is also an important factor for conducting investment activities on real estate. Previous analyses by researchers indicate that data on plots in the real estate registers are not sufficiently consistent. The aim of the article is to review the current situation with regard to the consistency of the basic data on land plots contained in the Land and Building Register and Land and Mortgage Registers on a selected example. The analysis by the comparative method was supplemented with the determination of the Jaccard index and the Russel-Rao coefficient. These are indices allowing to determine the degree of similarity between sets containing the same attributes.