The anionic forms of 26 drugs and organic model compounds have been extensively explored in the n-octanol/water system using voltammetry at three-phase electrodes. The objective of this study was to validate the ability of this electrochemical system to give reliable values of lipophilicity for organic ions, as well as to gain more information on the lipophilic behaviour of anions in the n-octanol/water system. Results were used to clarify the solvation mechanisms responsible for ion partitioning and to compare the information obtained in the two solvent systems n-octanol/water and 1,2-dichloroethane/water.