COSLA is an independent organization of the chief officers of state and territorial agencies designated as the state library administrative agency and responsible for statewide library development. Its purpose is to provide leadership on issues of common concern and national interest; to further state library agency relationships with federal government and national organizations; and to initiate cooperative action for the improvement of library services to the people of the United States. 

Its membership consists solely of these top library officers of the states and territories, variously designated as state librarian, director, commissioner or executive secretary. It provides a continuing mechanism for dealing with the problems and challenges faced by the heads of the state agencies which are responsible for statewide library development.

The work of COSLA is carried on through its members, a Board of Directors, and committees. The Chief Officers meet three times a year. The annual meeting is held in the fall, and working sessions are scheduled in conjunction with the mid-winter and Library Legislative Days of the American Library Association.

Concerns of COSLA include effective statewide planning and action to ensure library service adequate to meet the needs of all communities; the strengthening of state library agencies, library systems and effective networks; federal appropriations for library services; national library service programs; use of new technology for library and information service; state library services; availability of state and federal documents; improved library statistics programs; continuing library education programs; and state-federal responsibilities for talking book service to blind and handicapped persons throughout the nation.