The colloidal stability of polymer colloids with different functionality before and after adsorption of Triton X-100 has been studied. Experimental log W versus log [electrolyte] plots for bare particles were fitted using the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, and values of diffuse potential (psi (d)) and the Hamaker constant (A) were obtained. In the same way, log W versus log [electrolyte] plots for some latex-surfactant complexes were fitted using the extended DLVO theory, which considered steric repulsive interaction. Kinetic information was employed in order to reduce the number of fitting parameters of the steric repulsive potentials. In this way, the thickness of the stabilizing layer (delta) was the fitting parameter. We have found that the extended DLVO theory explains directly the results of some of the latex-surfactant complexes. However, in other cases, additional mechanisms had to be considered to explain the results. Ah these discrepancies could indicate that electrostatic and steric repulsion energies are not completely independent.