This book reports the interactions between the non-ionic polymer of ethyl(hydroxyethyl)cellulose (EHEC) and mixed anionic surfactant sodium dodecanoate (SDoD)-sodium, decanoate (SDeC) and sodium dodecyl sulfate (SDS) in aqueous media, at pH 9.2 (20 mM borate/NaOH buffer) were investigated by surface tension, electric conductivity and light transmittance measurements at 25 ?C. Some aspects of ethyl(hydroxyethyl)cellulose (EHEC) aqueous behavior in the presence of ionic surfactants are described in the literature; however, most of the studies reported deal with moderately concentrated solutions. Few studies have been carried out in the dilute regime using mixtures of anionic surfactants. The main proposal of this work is to investigate the interaction of EHEC in diluted regime and to verify the mixtures of the surfactants SDS, SDoD and SDeC. Through the results was not observed a specific link of polymer with the surfactant, implying therefore a phenomenon only cooperative association.