A unique number assigned to national economy entities and local units of these entities in the national official register of national economy entities REGON, with no implicit or explicit information on the features of an entity.

REGON identification number of legal units (legal persons, organisational units with no legal personality and natural persons conducting economic activity) consists of 9 digits, of which the first eight digits constitute a serial number, and the ninth - a control digit. REGON identification number of a local unit consists of fourteen digits, of which the first nine digits constitute identification number of a legal unit, the next four digits are a serial number assigned to the local unit, and the fourteenth digit is a control digit.

• Regulation of the Council of Ministers of 30 November 2015 on the Mode and Methodology of Running and Updating the National Official Business Register and Templates for Applications, Surveys and Certificates
  Place of publication: (Dz. U. poz. 2009, z późn. zm.)