A sensitive high performance liquid chromatographic (HPLC) technique has been used to determine the concentration and distribution of several α-keto acids and oxalic acid in seawater samples from a station (28°29′N, 128°38′W) in the eastern Pacific Ocean. Glyoxalic, pyruvic and oxalic acids were found to be present. Although the pyruvic acid profile at this station was in general featureless, the profiles for glyoxalic and oxalic acids showed variations which could be attributed to both primary production and heterotropic activity. Surface waters were found to have a combined concentration of glyoxalic and oxalic acids of ∼300 to 400 nm/liter which makes these two compounds some of the more abundant organic constituents of surface ocean waters.