The Main Library, which is the seat of library administration, is situated at Gonzalez Hall in the middle of the academic oval. It is organized into three major divisions which covers the various functional sections: (a) Technical Services Division which formulates and adopts standard acquisition, cataloging and indexing policies and procedures; (b) Administrative Services which provides support to the functional sections/units of the Library; and, (c) User Education and Services Division which lends books and provides reference, research and bibliographic services; maintains and preserve books, documents and archival materials; undertakes user education programs; and maintains computerized database applications.

It consists of eight (8) readers services sections (Filipiniana Book, Filipiniana Serials, Special Collections, Media Services, General Reference and Electronic Resources, Social Sciences, Foreign Serials, and the University Archives and Records Depository); four (4) technical sections (Acquisitions, Bibliography and Indexing / R & D, Cataloging and Computer Services); and the Administrative Services Department. Bulk of the library collection in the social sciences, general reference, foreign serials, UPiana and other special collections are found in the Main Library.

The Library’s print and non-book collection is complemented and updated by an extensive and multidisciplinary state-of-the-art electronic (CD-ROMs and online) databases which are accessible throughout the UP system. In the Main Library alone, there are 30 OPAC terminals in the first floor lobby and 24 CD-ROM/Internet browsers in the General Reference and Electronic Resources Section, made available to library users from 8:00 AM to 12 midnight on weekdays and from 8:00 AM to 5:00 PM on Saturdays. Several computers are also provided in the other sections for library clients and staff use as well. To safeguard and at the same time facilitate the circulation of library materials, a library security system with its prerequisite barcodes, barcode reader, magnetic strips, sensitizer-desensitizers and a closed circuit television were installed in the Main Library and other college/unit libraries.