Abstract A GLC method developed for the quantitative determination of lactic and succinic acids was studied collaboratively by six laboratories. Extracts of 25-50 g egg, with 1-86 mg lactic and 0.4–50 m g succinic acids added, were prepared in our laboratory by present AOAC procedures. The collaborators analyzed the extracts by formation of the propyl esters through reaction with BF3-ra-propyl alcohol reagent. Gas chromatography was performed with acetophenone as internal standard on a diethylene glycol succinate column using a flame ionization detector. The resulting peak heights were used to quantitate the acids. For samples containing less than 10 mg lactic acid and less than 14 mg succinic acid, 28 of 30 determinations were within 1.0 mg of the known a mounts . The standard deviations for these samples were all less than 0.6 mg. The overall per cent recovery for all samples averaged 105.2% for lactic acid and 101.9% for succinic acid. The method seems to give reliable results and to be as practicable as the AOAC methods.