The international ISSN Network comprises the ISSN International Centre in Paris and the national centres in various countries. The International Centre coordinates the activities of the Network, maintains the ISSN Portal database and issues ISSNs to the national centres. The Finnish ISSN Agency is responsible for assigning the identifiers in Finland and for sending the information on publications which have been assigned ISSN identifiers to the ISSN Portal. The Finnish ISSN Agency operates at the National Library of Finland.

The international ISSN Portal database features information on more than one million magazines, series and other continuing resources. The ISSN Portal receives approximately 50,000 new entries every year. The database has periodicals in approximately 150 different languages, demonstrating its global reach.

The ISSN Portal may be browsed free of charge, but regular users must subscribe to it. Further information on the database (including price list and order form) as well as on other ISSN products is available on the website of the ISSN International Centre.

The ISSN standard

Standards relating to ISSN identifiers include ISO 3297:1998 and SFS 4435:1998. The ISSN standard describes the ways in which ISSN identifiers may be used to identify continuing resources. A new version of the international ISSN standard, ISO 3297, was released in 2007.