International Identifier for serials
and other continuing resources, in the electronic and print world

Frequently Asked Questions

What is an ISSN ?

International Standard Serial Number

The ISSN (International Standard Serial Number) is an eight-digit number which identifies periodical publications as such, including electronic serials.

The ISSN is a numeric code which is used as an identifier: it has no signification in itself and does not contain in itself any information referring to the origin or contents of the publication.

The ISSN takes the form of the acronym ISSN followed by two groups of four digits, separated by a hyphen. The eighth character is a control digit calculated according to a modulo 11 algorithm on the basis of the 7 preceding digits; this eighth control character may be an “X” if the result of the computing is equal to “10”, in order to avoid any ambiguity.

The ISSN is linked to a standardized form of the title of the identified serial, known as the “key title”, which repeats the title of the publication, qualifying it with additional elements in order to distinguish it from other publications having identical titles.

If the title of the publication changes in any significant way, a new ISSN must be assigned in order to correspond to this new form of title and avoid any confusion. A serial publication whose title is modified several times in the course of its existence will be assigned each time a new ISSN, thus allowing precise identification of each form of the title : in fact it is then considered that they are different publications even if there is a logical link between them.

Contrary to other types of publications, the world of serial publications is particularly changeable and complex : the lifetime of a title may be extremely short; many publications may be part of a complex set of relationships, etc. These particularities themselves necessitated the introduction of the ISSN.

What is a “serial publication”?

A precise definition, which allows agreement on the exact field of application of the ISSN can be found in the IS0 3297 standard (ISSN): “A publication, in any medium, issued in successive parts, usually having numerical or chronological designations and intended to be continued with no predetermined end. NOTE : this definition excludes works intended to be published in a finite number of parts.(…) The ISSN is applicable to the entire population of serials, whether past, present or to be published in the foreseeable future. Serials include periodicals, newspapers, annuals (reports, yearbooks, directories, etc.), the journals, series, memoirs, proceedings, transactions, etc. of societies.”