The main function of the NLL is the collection of national literature, its eternal storage and long-term access.
The collection of the NLL (4,5 million units) embraces all branches of science, its basic profile being Social Sciences and the Humanities. Library readers are offered special collections - rare books, manuscripts, Letonica, the Baltic Central Library, maps, scores, sound recordings, graphic documents, small prints, periodicals. At present, most activities and events of the library are based on supporting higher education, research and life-long learning.
The NLL is a centre of theoretical research and practical analyses of the activities of Latvian libraries. The Library carries out the functions of the centre of Latvia Interlibrary Loan, ensures the library and information service to the Parliament of the Republic of Latvia, implements the standardisation of the branch. Since the very beginning its main focus has been the national bibliography.