Using a ternary gradient system, over 50 carotenoids, chlorophylls and their derivatives were separated from marine phytoplankton. Only 2 pairs of carotenoid pigments (19'-butanoyloxyfucoxanthin and siphonaxanthin, and 19'-hexanoyloxyfucoxanthin and 9'-cis-neoxanthin) and 3 chlorophylls (chlorophylls c1, c2 and Mg 2,4 divinyl pheoporphyrin a5 monomethyl ester [Mg2,4D]) were not resolved. Pigment chromatograms are presented for 12 unialgal cultures from 10 algal classes important in the marine environment: Amphidinium carterae Hulbert (Dinophyceae); Chroomonas salina (Wislouch) Butcher (Cryptophyceae); Dunaliella tertiolecta Butcher (Chlorophyceae); Emiliania huxleyi (Lohmann) Hay et Mohler and Pavlova lutheri (Droop) Green (Prymnesiophyceae); Euglena gracilis Klebs (Euglenophyceae); Micromonas pusilla (Butcher) Manton et Parke and Pycnococcus provasolii Guillard (Prasinophyceae); Pelagococcus subviridis Norris (Chrysophyceae); Phaeodactylum tricornutum Bohlin (Bacillariophyceae); Porphyridium cruentum (Bory) Drew et Ross (Rhodophyceae), and Synechococcus sp. (Cyanophyceae). A chromatogram is also given of a complex mixture of over 50 algal pigments such as might be found in a phytoplankton field sample. This method is useful for analysis of phytoplankton pigments in seawater samples and other instances where separations of complex pigment mixtures are required.