The interaction of magnesium and cadmium dodecyl sulfates (Cd(DS)(2) and Mg(DS)(2)) with poly(ethylene oxide) and poly(vinylpyrrolidone) (PEO and PVP) has been investigated in order to assess the effect of the surfactant counterion on the interaction. Electrical conductance, spectrofluorometry, and time-resolved fluorescence quenching were used to determine the critical micellar concentration (cmc), micelle ionization degree, surfactant binding range, and micelle aggregation numbers. Electrical conductance and cation self-diffusion measurements in solutions of NaCl, Cd(NO3)(2), and Mg(ClO4)(2) were used to study the binding of the cations to the same polymers. The results show that the interaction between dodecyl sulfates with divalent counterions and PEO or PVP and the interaction between sodium dodecyl sufate and the same polymers are qualitatively similar. The surfactant aggregation begins at a concentration lower than the cme of the surfactants investigated, the aggregation numbers of bound aggregates are lower than those for the corresponding free micelles and increase with surfactant concentration; and the bound aggregates are more ionized than the free micelles. The decrease in the aggregation number of the bound aggregates with increasing temperature was larger with PEO than with PVP, a result that can be explained in terms of the increasing hydrophobicity of PEO with temperature. In terms of bound charges per polymer repeat unit, the interaction of Cd2+ and Mg2+ ions with PEO or PVP is stronger than that of Na+ ions with the same polymers. The interaction strength thus follows the same sequence as the counterion degree of binding to free micelles. However, the values of the free energy of transfer of a dodecylsulfate ion from a free micelle to a polymer-hound aggregate are not very different with Na+ and divalent metal counterions, and are extremely small. The results obtained with the salt/polymer systems confirm the binding of cations by PEO and PVP in aqueous solutions.