National ISIL register

The National Agency for ISIL is the official representation of the International Standard Identifier for Libraries and Related Organizations (ISIL) for Bulgaria. The National ISIL Agency is authorized by the International ISIL Agency в Копенхаген, Дания и действа съобразно Инструкция за организацията и дейността на националната агенция за ISIL и приетите международни принципи.

National ISIL register

  • Defines and manages the structure of ISIL for Bulgarian libraries and related organizations;
  • Adjudge ISIL to Bulgarian libraries and related organizations;
  • Maintains a National ISIL Register with contact information and a brief description of the libraries and related organizations included in the ISIL system.

Information about ISIL


ISIL is International standard identifier for libraries and related organizations adopted as ISO standard (ISO 15511) in 2003. ISIL provides a means of unique identification of libraries and related organizations such as archives, museums, documentation centers or other organizations that work or interact with them such as suppliers, publishers and government institutions. ISIL may be assigned to each library or related organization, administrative or subordinate unit, acting alone, which is responsible for products or services in the information environment or carried out an international library or booktrade communication.

ISIL може да се определи за всяка библиотека или сродна организация, административна или подчинена единица, действаща самостоятелно, която е отговорна за дейност или услуга в информационна среда или извършва международна библиотечна или книготърговска комуникация.

In some cases, when an organization has undergone significant administrative change (e.g. merger with another organization), especially if this has led to a name change, a new ISIL identifier may be assigned.


ISIL provides standardized identification of libraries and related organizations to facilitate access to their information resources and services. It can seriously support the exchange of data, communication and interaction between organizations in the same or parallel sectors at national and international level.

ISIL is especially useful in activities such as:

    • interlibrary loan, document delivery and resource sharing,
    • development of national and international networks, union catalogs and other lists,
    • automated communication and processing of information in different technological applications, for example Radio Frequency Identification (RFID).


ISIL for the identification of Bulgarian libraries and related organizations include the following elements, separated by a hyphen:

a) country code prefix - identifies the country of the organization; It consists of two capital letters in accordance with the codes specified in ISO 3166-1.

Example BG = Bulgaria

b) unit identifier - numerical element designed to identify the library or related organization composed of the following parts:

  • code for location of organization (in accordance with geocodes for country’s 28 districts in accordance with ISO 3166-2: BG) - 2 digits;
  • code for type of organization - 1 or 2 digits;
  • serial number of organization - corresponds to order of registration - 4 digits.

Example BG-2240013

Conditions for inclusion inISIL

ISIL is assigned to Bulgarian libraries and related organizations free of charge after the completion and submission of the following registration form.

Please notify us of any changes in organizational data that occurred after registration using the same form.

The form can be sent to the following postal or e-mail address.

National ISIL register

Information on ISIL registered organizations (short description and contact details) received from the registration forms is included in a register and is published on the website of the "St. Cyril and St. Methodius" National Library and on the official website of ISIL ( as required by the International ISIL Agency. This is a prerequisite for expanding the international contacts of organizations and creating new partnerships. The register is accessible here.

Information in English is available here.


Address: Sofia 1504, 88 Vasil Levski Blvd.

"St. Cyril and St. Methodius" National Library
Tel.: +359 2 9183 218

Tel.: +359 878 915 992