Three new solvent systems are described for the separation of free and conjugated bile acids by glass fiber paper chromatography. An acidic solvent system consisting of isooctane-isopropyl ether-glacial acetic acid-isopropyl alcohol, 1:1:1:1: (v/v) was found suitable for the separation of glycineconjugated bile acids. A more polar modification of this acidic solvent system with chloroform substituting for isooctane, was found adequate for the separation of taurine conjugates. A basic solvent system consisting of chloroformisopropyl alcohol-ammonium hydroxide, 20:25:1 was found satisfactory for the separation of glycine and taurine-conjugated bile acids, and lecithin. © 1969, Oxford University Press. All rights reserved.