[See section My publication has been assigned an ISSN. How should I print / display it?]

If a publication is being relaunched with the same title, then the existing ISSN is still valid for use, even if there has been a publishing gap. No new ISSN should be assigned in this circumstance. If a serial reverts to a title that it held previously, a new ISSN needs to be assigned. The publisher cannot revert to using the previous ISSN.

Separate ISSN are needed for serials published in different physical formats. If your printed serial already has an ISSN and an online version is being produced for the first time, the online version is considered to be a new serial.

ISSN is assigned to a specific title. A new ISSN is usually needed if a title changes.

No, the ISSN is not related to ownership of a journal and does not confer copyright. A new ISSN will be required if the change of publisher results in a change of the serial title.

No, unlike the ISBN code, which contains country and publisher prefixes, an ISSN is an opaque identifier associated with a serial title, containing no information as to the publisher or its location.

Books (monographs) published within a series and annual / biennial publications are eligible for both ISBN and ISSN assignment.

An ISBN identifies an individual book in a series, or a specific year for an annual or biennial, and a different ISBN is used for every book.

When a serial is available in more than one physical format and a separate ISSN has been assigned to each format, the ISSN Network designates a linking ISSN (ISSN-L) from one of these ISSN. The ISSN-L is available for use when there is a need to identify and link to a continuing resource without regard to format, for example in services such as OpenURL, library catalogues, search engines or knowledge bases.

The ISSN identifiers are assigned at the request of publishers or third parties. ISSN are assigned either by ISSN National Centres for resources handled by publishers located in their respective countries or by the ISSN International Centre for publishers based in countries without a National Centre, for international organizations, or for multinational publishers having a specific agreement with the ISSN International Centre [see section 8. You are a publisher, or a third party requesting an ISSN assignment].

Publications that are issued over time with no predetermined conclusion, whether print or digital (online resource, application for mobile device, CD-ROM for instance): serials (journals, newspapers, magazines, monographic series...), ongoing integrating resource(s) (websites, databases...).