Chlorophyll-specific absorption coefficients of phytoplankton (aph) were determined in the upper 200 m along 150 degrees W in the equatorial and subequatorial Pacific, during the OLIPAC-JGOFS FRANCE cruise. A spectral reconstruction technique using the HPLC pigment information was used to partition aph into the contributions of photosynthetic pigments (aps) and non-photosynthetic pigments (anps). The values of aph were observed to decrease from the oligotrophic waters of the sub-equatorial area to the mesotrophic waters of the equatorial area, and from the surface to deep waters. These variations were primarily, but not exclusively, caused by changes in the concentrations of non-photosynthetic pigments. The level of pigment packaging was also variable, both horizontally as a result of changes in populations, and vertically as a result of photoacclimation. In comparison with aph, the chl-specific absorption coefficients of photosynthetic pigments (aps) exhibited a reduced range of variation with depth and from site to site. The variations in aps originating from the package effect were partly compensated by variations in the concentrations of photosynthetic pigments. In agreement with a previous study, we conclude that aps is less dependent on environmental parameters than aph. In addition, our results provide evidence that the variability in aps cannot be neglected. The use of aps instead of aph in light- photosynthesis models might present the advantage of eliminating the variability associated with non- photosynthetic pigments.