A procedure has been developed for the estimation of butyric, acetic, formic, succinic, and lactic acids in fermentation solutions. The acids are extracted by ether, separated by partition chromatography on a column of silica gel using benzene–butanol mixtures, and each determined quantitatively by titration with 0.01 N sodium hydroxide using phenol red as indicator. Recoveries are quantitative and determinations accurate within ± 2%. A method is also given for the quantitative separation and estimation of butyric, propionic, acetic, and formic acids, as well as a modified procedure for preparation of silica suitable for partition chromatography.