The ISWC (International Standard Musical Work Code) is a unique, permanent and internationally recognized reference number for the identification of musical works.

The ISWC is part of the CIS plan (Common Information System) which CISAC, the confederation of societies of authors, has developed in order to respond to the needs for information in the digital age.

The ISWC serves as a code to accurately, efficiently and quickly connect authors to a specific musical work. This code allows CMOs, publishers, music services and any stakeholder in the music value chain to track, identify and ensure that music creators are attributed the remuneration that is duly owed to them for the use of each specific musical work allocated an ISWC. 


The ISWC uniquely and accurately identifies each specific musical work. The identification methods of musical works (e.g., by work title) may result in confusion at times, particularly when multiple musical works share the same or similar titles. The ISWC is permanently attributed to a musical work, allowing identification of that musical work even if the work is distributed across countries and languages. The ISWC supports a wide range of software applications, including those involving in tracking and exchanging musical works information (e.g. registrations, identifications, royalty distributions).

The ISWC identifies musical works-not their manifestations, objects, or expressions (e.g. publications, broadcasts). The ISWC will not identify recordings, sheet music or any other type of performance associated with the musical work. Furthermore, the ISWC will not indicate the shares of composers or copyright owners of the work (often there are too many owners, which can change with time, territory and rights), nor the date or place where the work was initially created or published.


No, ISWCs are only assigned by the authorized local or regional Registration Agency. If the creators or publishers do not have a direct relationship with the local or regional Registration Agency, they may contact the Registration Authority for assistance. 

For new works, no steps are necessary. Works will be automatically assigned a number as part of the registration process. For previously registered works or "existing" repertoire, ISWC numbers may be assigned at any time.


Yes, the ISWC has been approved by ISO (International Organization for Standardisation). An official document defines how ISWC should be structured as well as the rules governing its issuance and application. An official ISO copy of the ISWC Standard can be purchased here.

The ISWC is administered by CISAC, the Registration Authority as appointed by ISO.

Registration Agencies are responsible for the assignment of ISWCs. These agencies are authorized to receive and process applications for ISWC. Once an application is processed, an ISWC number will be assigned to the musical work at the central registry. This central registry stores the ISWC numbers and their corresponding descriptive metadata. This central database makes available the ISWC public information among the music value chain (e.g., CMOs, publishers, sub-publishers, digital platforms, general public, etc.).

Yes, a modernisation project completed in 2020 has introduced several changes to the ISWC system to provide greater accuracy, more speed and increased efficiencies. All ISWCs are now assigned centrally to ensure a consistent approach and to improve metadata. Local Registration Agencies will continue to process documentation locally.


It is now easier to update metadata for existing ISWCs. Multiple ISWCs can now be merged together or separated should these assignments have been done in error. Registration Agencies can now flag works that appear identical (e.g., two unique songs with the same title assigned to the same creator) as unique works. The speed at which ISWCs are assigned has been dramatically reduced with codes becoming ready for usage within hours for all partners in the value chain (e.g., digital services, publishers, sub-publishers) to accelerate the ability to monetise works. 

An ISWC may be assigned to any musical work, published or unpublished, newly created or already existing including but not limited to: dramatic musical work, musical arrangement of a work, adaption of lyrics of a work, translation of lyrics of a work, a recognised excerpt of a work, or a medley.

For the sake of clarity, a musical work is composed of a combination of sounds, with or without accompanying text. Text only (lyrics) works cannot receive an ISWC.

Musical arrangements, adaptations of lyrics and translations must receive their own unique ISWC numbers. These ISWC numbers are usually allocated by the agency which administrates the works of the arranger and/or adapter. The connection between the 'version' and the original work is indicated in the descriptive metadata of the ISWC.

All works should be identified in their own rights. For example, an aria from an opera or a cadenza from a concerto can receive an ISWC. Similar to the 'versions', the relationship between excerpts should be indicated in the descriptive metadata of the ISWC.

Surprisingly, the answer is "yes". The non-authorised arrangements of a musical work can be identified, if only to ensure that they will be recognised at an international level as works infringing the copyrights of others.

No. ISWCs are allocated regardless of copyright status. Registration Agencies may 'adopt' authors from the "public domain", according to their local laws, and assign ISWC numbers to their works. This is generally done for reasons of national interest. For example, the 'traditional' folk repertoire, works in the public domain whose authors are unknown, can be numbered by an authorized local Registration Agency.

An ISWC begins with the letter "T", followed by a unique nine-digit number (from 00000001 to 999999999) with an additional check digit at the end. (Written format: T-345246800-1).

The descriptive metadata for an ISWC includes: 

  • The title of the work;
  • All composers, authors and arrangers of the work identified by their IPI numbers and role codes;
  • In the case of 'versions' (e.g., arrangements), identification of the work from which the version was derived.

An ISWC cannot be allocated without this minimum, required information.

The ISWC should be integrated within the musical works administration databases and processes that support activities such as: 

  • Registration and correspondence between CMOs
  • Publishing and sub-publishing agreement schedules
  • Licenses granted by a society
  • Music usage reporting
  • Performance collection and identification
  • Royalty administration.

When a musical work in correspondence or in contracts is identified, the ISWC should be indicated as in the following example:1.1 "I Love Life" (Smith/Jones) (ISWC T-345246800-1)

An ISWC code is only allocated by the local Registration Agency when all of the creators of the work have been uniquely identified.

The internal rules of ISWC administration as stated in the agreement with the Registration Authority, which are amended from time to time.

No. Most organisations will still require their own internal identification numbers for internal reasons. On the other hand, the ISWC is the 'lingua franca' that allows databases to be linked automatically

Nothing happens because the ISWC is permanently assigned to the musical work