The paper presents a proposal for the data security model to protect the cadastral information recorded in the databases of real estate in Poland. The model was developed for the implementa- tion of multi-purpose cadastral tasks. The problem has been considered from the point of view of the smooth functioning of the real estate market. Reliability of the real estate market is guar- anteed by the full, accurate, easily available and current cadastral data. The latter is an important piece of information about the area or land, essential for the implementation of most of the real estate management processes. The publication indicates obligatory and optional sources of cadastral information. The basis for the model of cadastral data security system is the compat- ibility of the assumptions between the said model and the applicable law. The model contains four types of disclosure status for cadastral data (confidential information, public information, incomplete public information, non-confidential information requiring a license). The status was adjusted to specified groups of users of the multipurpose cadastre. The aforementioned groups are based on the entities, acting within the real estate market in Poland. The security model presented herewith assumes a full transition to computer storage media, including the descriptive information and spatial databases, contained in the multi-purpose cadastre, as well as full interoperability of the data collected therein.