Frequently Asked Questions (FAQ)

Network Development and MARC Standards Office
Library of Congress

General Information

MARC 21 Documentation

MARC 21 Tutorials

MARC, SGML, XML and other metadata standards

MARC 21 Translations

Tools, Systems and Services That Work With MARC 21

Making Changes to the MARC 21 Formats and Code Lists

Record Requirements and Record and File Specifications for MARC 21

Electronic resources and MARC 21


General Information

What is MARC 21? What does the acronym “MARC” mean?

MARC is the acronym for MAchine-Readable Cataloging. It defines a data format that emerged from a Library of Congress-led initiative that began nearly forty years ago. It provides the mechanism by which computers exchange, use, and interpret bibliographic information, and its data elements make up the foundation of most library catalogs used today. MARC became USMARC in the 1980s and MARC 21 in the late 1990s.

How does MARC 21 differ from the USMARC and CAN/MARC formats?

MARC 21 is not a new format. After having discussions and making minor changes to both formats that accommodated USMARC and CAN/MARC users' specific needs, the USMARC and CAN/MARC (Canadian MARC) formats were “harmonized” into MARC 21 in 1997. See http://www.loc.gov/marc/annmarc21.html for more information about the harmonization.

Who maintains the MARC 21 formats?

The Network Development and MARC Standards Office at the Library of Congress and the Standards and the Support Office at the Library and Archives Canada maintain the MARC 21 formats. Input for development is provided by MARC 21 users from around the world, including libraries, library networks and utilities, and library system vendors. See http://www.loc.gov/marc/overview.html for more information about the development and maintenance of the formats.

What are the Network Development and MARC Standards Office and the Standards Division?

The Network Development and MARC Standards Office plans and develops library and information network standards at the Library of Congress. It is the maintenance agency for several national standards, including the MARC 21 formats.To contact it, please e-mail ndmso@loc.gov.

The Standards Division at the Library and Archives Canada maintains and supports the MARC 21 formats and other library standards. To contact it, please e-mail marc@lac-bac.ca.

Are there any discussion groups or forums for the MARC 21 formats?

The MARC Forum is a listserv maintained by the Network Development and MARC Standards Office and is open to anyone interested in the implementation, maintenance and development of the MARC 21 formats. The forum provides an opportunity for members of the information community to participate in discussions related to the formats. Vendor, network, technical service, automation, and reference staff and researchers are encouraged to participate. While there is a close linkage between MARC 21 and the cataloging of materials, the focus of the forum is on the use of MARC 21 as a communications format.

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MARC 21 Documentation

What documentation is available and and how do I obtain it?

The MARC Standards page has links to both extensive documentation on MARC 21, including both the full and concise formats, code and field lists, information about MARC 21 development, and documentation to help users with the MARC 21 format. There is a format overview listing changes to MARC documentation. Some documentation is also available in translation. A bibliography is also available on the Library's MARC Standards webpage.

Documentation of French versions of some of the formats in Canada is available at Library and Archives Canada.

How often is MARC 21 documentation updated?

The MARC 21 formats are updated two times per year, in the spring and fall. Other documentation is updated as it becomes necessary.

May I use excerpts from MARC 21 documentation?

Using excerpts is permissible as long as credit is given.

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MARC 21 Tutorials

Is there a tutorial for the MARC 21 formats?

Understanding MARC Bibliographic is a good introduction to the MARC 21 bibliographic format and includes a bibliography, discussion questions and examples. It is widely used and has been translated into several different languages.

Understanding MARC Authority Records is a good introduction to the MARC 21 authority format and includes a bibliography, discussion questions and examples.

Both Understanding MARC Bibliographic and Understanding MARC Authority Records are also available as booklets from the Cataloging Distribution Service.

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MARC 21, SGML, XML and other metadata standards

Are SGML or XML versions of the MARC 21 formats available?

The Network Development and MARC Standards Office has developed a framework for working with MARC data in a XML environment. This framework is intended to be flexible and extensible, allowing users to work with MARC data in ways that meet their specific needs. The framework contains many components such as schemas, stylesheets, and software tools developed and maintained by the Library of Congress. Conversion utilities between MARC (ISO 2709) and MARCXML are also available. Please see www.loc.gov/marc/marcxml.html.

The Network Development and MARC Standards Office also developed a MARC to SGML and SGML to MARC conversion program. The following documents contain the program and additional information:

A list of some tools that work with HTML, SGML and XML applications is at http://www.loc.gov/marc/marctools.html.

Is MARC 21 mapped to other metadata standards? Are other standards mapped to MARC 21?

MARC 21 has been mapped to the following metadata standards:

The following metadata standards have been mapped to MARC 21:

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MARC 21 Translations

Are there any translations of the MARC 21 formats?

The MARC 21 Translations page contains a list of documents that are either direct translations or close adaptations of the MARC 21 formats and other MARC documentation. Where applicable, information regarding differences between the translations and MARC 21 is provided. The formats are listed alphabetically by the language of each translation and include full bibliographic citations and contact information.

I would like to translate a MARC 21 publication. What should I do?

Translations of the MARC 21 formats and other MARC documentation are greatly encouraged because of their usefulness to the entire MARC 21 community. The Network Development and MARC Standards Office does ask that intellectual credit information be included in the translation. The following statement is recommended: “The MARC 21 [insert name of publication that was translated] was originally prepared by the Network Development MARC Standards Office, Library of Congress and the Standards Division, Library and Archives Canada. It has been translated with permission.” Once you complete your translation, please send the Network Development and MARC Standards Office an official announcement that includes your publication's bibliographic information and contact information on obtaining copies. If possible, send a printed copy for our collection of translations. If the translation is available on the Internet, please include its URL for inclusion on the MARC 21 Translations page. Listing a translation is not mandatory; however translations are extremely useful to other MARC 21 users.

A Translators's Tools page contains additional information about translating MARC 21 documents.

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Tools, Systems and Services That Work With MARC 21

Is there a list of tools compatible with the MARC 21 formats?

A list of some of the bibliographic tools that support the MARC 21 formats is at www.loc.gov/marc/marctools.html. It includes software programs that provide enhanced usability to MARC 21 records and systems. Some of the tools are freeware or open source.

Is there a list of MARC 21 record services?

A list of some of the record services that support the MARC 21 formats is at www.loc.gov/marc/marcrecsvrs.html. It includes services that distribute MARC 21 records, such as records for copy cataloging, records supplied with materials, records used for recon purposes, updated records, conversion services, etc.

What systems are compatible with the MARC 21 formats?

A list of some of the systems that support the MARC 21 formats is at www.loc.gov/marc/marcsysvend.html. The list includes systems that collect, organize and manage MARC 21 records.

How do I add a record service, vendor system or tool to these lists?

Vendors, software producers, and anyone else who provides vendor records, system services, or who has developed specialized MARC tools, are encouraged to fill out a submission form.

Please note: Individuals who submit the form on someone else's behalf should put their contact information in the “Citation Contact” field and the name of the individual/company on whose behalf the form is submitted in the “Product Contact” field.

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Making Changes to the MARC 21 Formats and Code Lists

How do I report errors in MARC 21 documentation?

If you notice an error or omission in either the print or online MARC 21 documentation, please contact ndmso@loc.gov. Describe the error and where it occurs. Please be as specific as possible.

How do I propose making a change to the MARC 21 formats?

Proposals for changes to the formats may originate from any MARC 21 user. Please either fill out the MARC 21 Formats Proposed Change Form or contact the Network Development and MARC Standards Office at the Library of Congress or the Standards division at the Library and Archives Canada. Maintenance agency staff at the Library of Congress and the Library and Archives Canada write, edit and review proposals and discussion papers twice a year and distribute them via the MARC Forum listserv and the MARC Standards web site. Discussions at the semiannual MARBI (Machine-Readable Bibliographic Information) meetings in the United States and the annual CCM (Canadian Committee on MARC) meeting in Canada, along with suggestions received by e-mail and the listserv, are used by the maintenance agencies to make final decisions on the proposals.

How do I request new or revised MARC 21 organization codes?

Before requesting a MARC 21 organization code, please first search the MARC Code List for Organizations. If you do not find a code for your organization, click on one of these links to access a request form in the language of your choice.

You may use the online form to request up to three codes. If more than three codes are needed, please submit a list of the organizations with their names and addresses (including street, city, state, postal code, and country) via email to ndmso@loc.gov Please include contact information. Note: Attachments to e-mail messages are not accepted.

The MARC Code List for Organizations is updated frequently, as codes are often added. Since information in a request must be verified and then incorporated into the list, there is a short delay between the time of the request and the appearance of a newly-assigned code in the database. Names and addresses are revised when changes are reported.

Requests for the assignment of new codes or changes involving organizations in Canada should be sent to the Interlibrary Loan Division at the Library and Archives Canada.

Requests for the assignment of new codes or changes involving organizations in the United Kingdom should be sent to the UK National Agency for MARC Organisation Codes at the British Library.

Requests for the assignment of new MARC organization codes or for changes to codes may also be sent via fax to +1-202-707-0115 or by surface mail to:

Library of Congress
Network Development and MARC Standards Office
101 Independence Avenue, S.E.
Washington, DC, 20540-4402 USA

How do I request MARC 21 relator, sources or description convention codes?

Requests for relators, sources or description convention codes should be sent to ndmso@loc.gov.

Requests can also be faxed to +1-202-707-0115 or sent by surface mail to:

Library of Congress
Network Development and MARC Standards Office
101 Independence Avenue, S.E.
Washington, DC, 20540-4402 USA

Requests should include a full bibliographic citation and a scan, photocopy or Internet link for the item to be added.

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Record Requirements and Record and File Specifications for MARC 21

Where do I find the U.S. National Level/Minimal Level Record Requirements for the MARC 21 formats?

There is no list of of “mandatory” data elements that must appear in a MARC 21 record. Thereotically, a record could simply consist of a leader and a 245 (title) field. However, there is a list of the MARC 21 data elements required to meet minimal and national level requirements in the United States for the bibliographic and authority formats. Please note that other countries may have different lists of required data elements.

What are the appropriate record and file specifications for the formats?

Information about the file specifications for the MARC 21 formats is in MARC 21 Specifications for Record Structure, Character Sets, and Exchange Media. This document is also available from the Cataloging Distribution Service. For a basic introduction to MARC 21 file and record structure, you may also want to look at Understanding MARC Bibliographic.

What are the specifications for character sets?

MARC 21 records intended for broad, standard interchange should be encoded according to the following specifications. Either an 8-bit based encoding system (called MARC-8 in MARC 21 documentation) or a variable 8/16-bit encoding following ISO/IEC 10646 (UCS) and Unicode UTF-8 encoding rules (called UCS/Unicode UTF-8 in MARC 21 documentation) may be used.

A very large repertoire of characters is defined for use in the MARC-8 environment. For standard MARC 21 interchange, the use of UCS/Unicode UTF-8 is limited to this same repertoire, a subset of UCS/Unicode. This is necessary for interchange until all systems fully accommodate the complete UCS/Unicode repertoire of characters. This restriction will be periodically reviewed as the character encoding environment develops.

Please see http://www.loc.gov/marc/specifications/speccharintro.html for detailed information on MARC 21 character sets.

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Electronic resources and MARC 21

How do I code electronic resources in a MARC 21 record?

The document Guidelines for Coding Electronic Resources in Leader/06 assists users coding fixed fields in records for electronic resources. Guidelines for the Use of Field 856 provides guidance on using field 856 (Electronic location and access) in all the MARC 21 formats. Guidelines for Distinguishing Cartographic Electronic Resources from other Electronic Resources assists catalogers working with cartographic electronic resources.

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