The department is responsible for the following:

1. Preparation and maintenance of appropriate selection and acquisition policy for the National Library of Nigeria;
2. Systematically selection current and relevant information and educational materials that could meet the needs of the populace;
3. Acquisition of materials for the National Library of Nigeria through subscription/purchases;
4. Checking, accessioning and central processing of materials received from the National Library stores, legal deposit department as well as gifts and exchange;
5. To formulate plans and policies for the development of effective national bibliographic control in Nigeria, by providing full bibliographic description for all Nigerian materials in accordance with international standards;
6. To develop uniform standards for cataloguing and classification based on the different texts of international standards for bibliographic description which are effective tools for bibliographic control;
7. To provide necessary support to the International Standards and programmes Department (IS&PD) in carrying out the Cataloguing-in-Publication (CIP) programme of the institution;
8. To prepare catalogues, classification tools and similar research aids;
9. Introduce international and national standards, methods, and norms for book processing, through organizing seminars and workshops, interaction and cooperation with other national bibliographic agencies rendering similar services in Africa and other parts of the world.
10. Identifying possible sources of books and other gift materials for the National Library of Nigeria;
11. Acquiring books and non-book materials through gifts and exchanges, as well as donations from well-meaning individuals and organization;
12. Ensuring that such gifts are channeled for appropriate use and acknowledged accordingly;
13. Soliciting for book aid from overseas on behalf of the National Library of Nigeria;
14. Encourage authors and other people in possession of manuscripts to donate them to the National Library of Nigeria so as to ensure their preservation for posterity.
15. Partner with National and International agencies in the exchange of their intellectual works;
16. Regular stock taking and evaluation of information materials in the library to determine those that are bad and require repair;
17. To frequently liaise with other departments/branches in identifying those information materials that needs to be repaired/restores for optimal use;
18.  To identify strategies to preserve and conserve information materials in the National Library of Nigeria, such as proper handling of books, guarding against theft and mutilation, provision of functional fire extinguishers etc;
19. To determine appropriate time/period for fumigation of information materials, library building and its environment;
20. To propose an appropriate preservation and conservation policy for National library of Nigeria;
21. Sensitize/enlighten staff and library users against acts that can cause damage to books and other information materials in the library.

The department comprises of three (3) main divisions and ten (10) sections.

Selection and Acquisition Division
It is responsible for acquiring materials through subscriptions/purchases in accordance with the guideline provided in the acquisitions policy.

Sections:

• Selection Section 
• Receipt and Processing Section
• Database Management Section
• Preservation and Conservation Section

Cataloguing and Classification Division
The division is statutorily responsible for the central technical processing of intellectual resources acquired through purchases and gifts.

Sections:

• Nigeriana Monographs  Section
• Non-Book/Serial Section
• Foreign Monograph Section
• Shelf Preparation Section

Gifts and Exchange Division 
It is responsible for acquiring books and non-book materials through gifts and exchanges as well as donations from well-meaning individuals and organizations.  It is also charged with the responsibility of soliciting for gifts from foreign donors for distribution to educational institutions.

Sections:

• Gifts Section
• Exchange Section