Abstract: A two-day Conference hosted by NBS was held in Gaithersburg, Maryland on May 14-15, 1986 to test the hypothesis that "There is a need for a coordinated methodology for accrediting construction materials testing laboratories." Construction materials include primary materials such as: cement, concrete, aggregates, rock and soil, asphalts, metals, wood and masonry. The Conference was structured to consider: (1) the status of existing laboratory evaluation and accreditation programs; (2) current trends in the accreditation process; and (3) the need for and nature of a coordinated accreditation system. The Conference included the presentation of invited papers and four workshop sessions.