The surface tensions of aqueous solutions of a mixture of cetyltrimethylammonium bromide (CTAB) and hexaethylene glycol mono-n-dodecyl ether (C(12)E(6)) were measured as a function of the total concentration and composition of surfactants at room temperature (298 K). Using the phase separation model for mixed micellization, the interaction parameter beta and the compositions in the mixed micelles are evaluated. A combination of the Langmuir isotherm and the Gibbs equation is used to explain the adsorption behavior of the mixtures. A synergistic effect is observed for adsorption at the surface at a low mole fraction of CTAB. This fact is further confirmed from the fluorescence emission spectra of a pyrene probe in mixed micelles.