The National Centres of the ISSN network are generally part of the National Library or of the main documentation institution of the country concerned and are able to achieve control of the editorial production of serials throughout their national territory.
Bibliographic control is achieved through legal deposit.
The work of Union catalogues can often help to complete the data they have already obtained. The ISSN International Centre, besides its tasks of maintenance and edition of the ISSN Register and of control of the activities of the National centres of the network, is also in charge of ISSN assignment for international publications and for the publications from countries with no National Centre. The ISSN International Centre is an intergovernmental institution governed by Statutes to which Member States accede. These Statutes are the object of a Convention between Unesco and France, the host country of the International Centre. Each user of the ISSN, each serial publisher, has the possibility of asking for the assignment of ISSN to publications which have not yet been registered by the network, by contacting to the National Centre concerned or the ISSN International Centre.