Universal Machine Readable Catalogue (UNIMARC)

Universal Machine Readable Catalogue (UNIMARC): There emerged a number of standard bibliographic record formats such as UKMARC, INTERMARC, USMARC, etc whose paths diverged owing to different national cataloguing practices and requirements. Since the early 1970s, an extended family of more than 20 MARC formats has grown up. To greater or lesser degrees almost all formats are compatible but the differences in data content mean that editing is required before records are exchanged. Recognizing that there is a need for the establishment of international format for the exchange of bibliographic data, IFLA, the section on cataloguing and mechanization, took the initiative to develop international MARC format which would accept the record created in any MARC format. As a result, the first version of Universal Machine Readable Catalogue (UNIMARC) appeared for monograph and serial in 1977 to facilitate the international exchange of bibliographic data in machine readable form. UNIMARC follows the ISO communication format ISO-2709 (1981).


Besides MARC family of formats, there are other formats, notable among them being AGRIS, International Nuclear Information System (INIS), UNISIST Reference Manual, UNESCO’s CCF as a universal exchange format for bibliographical record.

            Every national organization producing MARC records will produce them in the national standard for use within the country and will reformat them according to UNIMARC format for international exchange. So, after the development of UNIMARC each national agency would need to write only two programmes- one to convert into a UNIMARC and the other to convert from UNIMARC,  instead of one programme for each other MARC format. Eg. INTERMARC to UKMARC, USMARC to UKMARC, and so on.

a) UNIMARC Format: The UNIMARC format like any other version of MARC involves three elements of the bibliographic record. These are-

i) Record Structure: The record structure is designed to control the representation of data by storing it in the form of strings of characters known as fields. By record structure various elements in a record structure are identified.

ii) Content Designation: Certain conventions are followed in order to identify the data element within records. Such elements which include author, title and subject access are further characterized. This supports the manipulation of the data for a variety of purposes.

iii) Data Content: The content is the data which is stored in the fields within the record. Data can be coded data or bibliographic data.

b) Functional Block of UNIMARC: The fields which are identified by three character numeric tags are arranged in functional blocks. These blocks organize the data according to its function in a traditional catalogue record. The data element and content of the record have been functionally divided into 10 different types of block. These are shown below:


Block no

Field tag

Data Type




Identification Block

Contains numbers that identify the record.

Eg. 010  International Standard Book Number.



Coded Information Block

Contains fixed length data element describing various aspect of the record or data.

Eg. 101 Language of the work



Heading Block

Contains the authority, reference or general explanatory heading for which records have been created.

Eg. 205 Edition statement




Information Note Block

Contains note, intended for public display that explain the relationship between the record heading and other heading.



See Reference Tracing Block

Contains variant heading from which a reference is to be made to see the heading of the record.

Eg. 452 Edition in a different medium



See Also Reference Tracing Block

Contains related uniform heading from which a reference is to be made to see also the heading of the record.

Eg. 516 Spine title



Classification Number Block

Contains classification number that are related to the heading of the record.

Eg. 676 Dewey Decimal Classification.



Linking Heading Block

Contains a form of the record heading in another language or script and links to another record in which that form is the heading.

Eg. 700 Personal name



Source Information Block

Contains the source of the record and catalogues notes about the data not intended for public display.

Eg. 801 Originating Source



National use Block

Contains data local to the originator of the record.


            It is anticipated that each national bibliographic agency will be responsible for the conversion of authority record into UNIMARC / Authorities for transmission to other national agencies and will receive machine readable record in the UNIMARC / Authorities format from other national agencies. Despite much efforts of IFLA, UNIMARC failed to receive due consideration.