This report assesses the quality and effectiveness of the NIST measurements and standards laboratories, of which there are now six, including two user facilities, as well as the adequacy of the laboratories' resources. An Assessment of the National Institute of Standards and Technology Center for Neutron Research considers the merit of the current NCNR scientific and technical programs relative to current state-of-the-art programs; the degree to which the NCNR scientific and technical programs achieve their objectives and fulfill the mission of the NCNR; and the adequacy of the NCNR facilities, equipment, and human resources, as they affect the quality of the NCNR's scientific and technical programs.