The effects of volume ratio, of surfactant and alcohol concentrations, and of different ions on the ion distribution oi. a dioctyldimethylammonium chloride-decanol-isooctane reverse micellar phase in equilibrium with an aqueous phase were studied. The initial organic phase containing the surfactant and decanol, as cosurfactant, in isooctane was contacted with an aqueous phase containing electrolytes. Experimental data of the distribution anions in this system have been measured at 23 degrees C. A mathematical model has buen developed which accounts for the exchange of the surfactant counterion with the anions in the aqueous phase. This model uses one single parameter for each anion, which depends only on the nature of the anion. It accurately represents the distribution of anions between the two phases of the system. Dimensionless groups have been employed to combine the effect of several independent variables into a few groups.