The chromatographic characteristic of 58 phenols on Rexyn 102 and Dowex 50-X4 thin layers in both the acidic and sodium salt forms have been studied, using elution with water, water-alcohol mixtures and aqueous salt solutions at different pH values. The influence of the percentage of alcohol, the pH and the ionic strength on the chromatographic behaviour of these phenols was investigated. The validity of the relationships among the R F values, the pH of the eluent and the p K a of the phenol has been verified on Dowex 50-X4 (Na =) thin layers. It has been shown that from the R f ac , R F alk and p K a values of the different phenols, it is possible to predict their behaviour over the whole pH range and therefore to select the best conditions for their chromatographic separation.