Reliable analytical measurement of photosynthetic pigment concentrations is crucial to the success of numerous mesoscale oceanographic programs (JGOFS, GOFS, WOCE, NASA, etc.). For these multi-investigator, multi-year programs standard and/or minimum precision, accuracy, and representativeness guidelines must be established to avoid the acquisition of biased, meaningless or unreliable results. Any program that acquires data over long periods of time and/or from many different laboratories needs a mechanism to insure the integrity and continuity of the data base that is being acquired. The activities described here are a first attempt to establish guidelines and set realistic and meaningful precision, accuracy and representativeness goals for photosynthetic pigment measurements. Based on the recommendations outlined in the GOFS/JGOFS planning reports, this study will (1) develop and implement a quality assurance program for the analysis of plant pigments by HPLC; (2) provide external and internal pigment standards to laboratories participating in the GOFS/JGOFS (and related) programs; and (3) coordinate intercalibration exercises among laboratories participating in the GOFS/JGOFS programs.