From its establishment the National Library was entrusted with tasks necessary for the support of cultural and historical traditions of the country. The furthering of these tasks made it possible for the Library to assume the status of a national library.

The Library gathers and processes bibliographic information, stores it and provides the Bulgarian and foreign public with printed matter and audiovisual documents created in Bulgaria.

Following the adoption of the Legal Deposit Act all printed matter in the country has been deposited for over a century. The Deposit of audio-visual documents began with the coming into force of Decree of the State Council 1367 of 1976, and from the beginning of the year 2000 the obligatory deposit of printed matter and electronic documents. This deposited material has called on the Library to carry out the following:

  Organize and preserve the unique Archive of Bulgarian literature.
  Organize and maintain library collections at the disposal of all adult Bulgarian and foreign citizens.
  Compile and publish Bulgarian current and restrospective national bibliography, which is distributed through current and commulative periodical editions or machine-readable carriers.
  Exercise control over the realization of normative documents on the mandatory deposit of printed matter and other publications and distributes copies of Bulgarian printed matter for other deposit libraries in the countries.
  Carry out centralized cataloguing of Bulgarian books.
  Prepare statistical data on publishers activities in the country.
  Provide the International Centre for ISBN in Berlinwith information on the address of Bulgarian publishers and the International ISSN Centre in Paris with bibliographic information on periodicals, published in Bulgaria. Compile the annual publication in Bulgaria on the section on translation of literature coming out in Bulgaria as well as the UNESCO data base Index translationum.

The Library gathers, preserves and processes Bulgarian, Slavic and Oriental manuscripts, archival documents and rare and valuable old printed books, making them available to researchers. The valuable collections of this material allow the following:

  The compiling of a reference guides for this material, publish lists and catalogues and facilitate their use by a wider circle of researchers in Bulgaria and abroad.
  Concrete research by the staff of the Library.
  Carrying out regular research on the discovery and publication of unknown documents, connected with Bulgarian history and literature.
  The organization of exhibitions and other events in the Bulgaria and abroad popularizing Bulgarian letters and the cultural heritage.

The Library builds up, preserves and makes available a representative collection of foreign academic literature in all fields of knowledge. Special attention is shown in the current acquisition of the following:

  Editions published in Bulgarian or connected with Bulgaria in its content;
  Translations of books by Bulgarian authors, published abroad;
  Basic reference books, encyclopaedias, bibliographies and bibliographic databases;
  Representative foreign monographs in separate fields and bordering scientific fields;
  Current subscription of leading foreign scientific journals and papers;
  Оfficial editions of separate countries or international organizations;
  Specialized professional literature in the field of bibliographic-informational sciences and informatics.

As a research institution the Library carries out research in the field of library science, bibliography, book publishing, archive studies, restoration and conservation of written material. The variety of researchers in the Library work on the following themes:

  Studies on theory and practice of library, bibliographic and archival activities;
  Bibliographies and lists of documents connected with considerable personalities, events and public processes related to national culture;
  Monographs on cultural, historical and a literary-historical themes related to documentary sources from the collections of the Library.

The results of these research activities, together with studies at other libraries or institutions, linked with books and information published by the National Library within its specialized periodical professional editions, namely:

  Известия на Народната библиотека “Св. Св. Кирил и Методий” (Annals of the National library, coming out since 1952)
  Списание “Библиотека” (Journal "Biblioteka", coming out since 1954)

The Library participates in the building up and functioning of a national information infrastructure, in which namely:

  Creates and offers bibliographic records for Bulgarian documents;
  Creates, organizes and distributes bibliographic information about foreign books and periodicals in Bulgaria through the Union catalogues it maintains;
  Participates in the standardization of library-bibliographic processes in Bulgaria;
  Gathers statistical information on publishing, printing activities and librarianship and presents it to the National Statistical Institute;
  In its position of a seat of the national agencies on international standard numbering of books and periodicals (ISBN and ISSN) provides numbers to publishers in Bulgaria, gathers and publishes information on books in print and the addresses of publishers, and the editorial boards of periodicals;


 The Library has been an active participant in expanding cooperation between libraries in Bulgaria and abroad and the building up of a national library system through a variety of activities:

  Maintains a book exchange with many libraries in Bulgaria and abroad;
  As the largest library in Bulgaria and deposit library it is the centre of the inter library loan service in Bulgaria and abroad;
  Participates through its information resources in the building up of a National Automated Library Information Network (NALIN);
  Provides expert services in the field of library science, bibliography, book science, automation of library processes and restoration, conservation and protection of library collections to libraries in Bulgaria and other organizations and private persons;
  Organizes and takes part in professional conferences, meetings, and seminars in Bulgaria and abroad, organized by other institutions;
  Is a member of the Council of directors of the major research libraries in Sofia and through its representatives participates in the activities of professional commissions of the council at various institutions;
  Is a member and works with international professional organizations (International Federation of Library Association IFLA), The International Information Bank of French-speaking countries BIEF, the Conference of Directors of European National Libraries - CENL, the Network of Association of Libraries under UNESCO - UNAL, the International ISBN Center and ISSN Network etc.;
  Participates through its staff in drawing up of joint projects for the development of library technology (The Project for the Building up of a National Automatic Library-information Network 1993, the National Programme for Preservation of Library Collections - 1997), projects for normative documents in the field of librarianship (Regulations of the Ministry of Culture for the Protection of Library Collections, 1995, drafts for the Library law, for the Legal Deposit Act, and for the National Library 1993, 2000, 2004 etc.).

 In its capacity of a national cultural institution the National Library participates in numerous initiatives within the framework of cultural life in the country. This is realized over continuous cooperation with related institutions, both involved with certain activities and in the realization of separate projects or assignments:

  The library is the seat of the Bulgarian Archeographic Commission, which coordinates and encourages researchers of manuscripts from various institutions;
  The library is one of the founder institutions - of the Technical Committee on Archival, Library and Information Activities (TC16 on ALIA) under the Bulgaria Institute for Standardization, which unites and pools the work of over 15 organizations for cooperation in the field of standardization;
  The library maintains long-term cooperation with the Chief Board of Archives, the National Historical Museum, the National Museum of Literature, the Church Historical Archival Institute at the Holy Synod of the Bulgarian Patriarchate and a number of other cultural institutions entrusted with a historical heritage of the nation;
  The library has been cooperating with a number of NGOs and foundations. Within the range of this cooperation falls collective membership in professional organizations (The Union of Librarians and Information Services Officers - ULISO), as well as on joint projects with organizations funding cultural activities (Open Society Fund, the 13 Centuries Bulgaria Endowment Fund, the Future for Bulgaria Foundation etc) or guilds of close professions (the Association of Publishers, the Union of Bulgarian Writers, the Association of Bulgarian Writers, the Union of Translators in Bulgaria, etc).

Through the work of the largest laboratory for restoration and conservation of printed matter the National Library is the leading institution in the efforts for preservation of the national written heritage.