This paper presents the investigation of interaction of chitosan with carboxylate surfactants -cetyl oligo ethylene succinate and 1-stearoyl-2-hydroxypropyl-3-succinate. It is shown that depending on the type of surfactant and the ratio of components, viscous solutions or colloidal dispersions form on interaction with chitosan. For solutions of chitosan -surfactant derivatives a significant non-additive decrease in surface tension is characteristic, making them useful for obtaining stable emulsions of oil in water.Much attention is devoted to the investigation of the interaction of low molecular weight surface-active agents (surfactants) with natural and synthetic polymers [1,2]. In a number of publications it has been shown that the type of anion-active surfactant has a significant effect on the colloid-chemical properties of the surfactant-polyelectrolyte complexes [3,5]. It is noted that the surface activity of sodium dodecyl sulfate (SDS) -cationic polymer complexes is a function of the length of the alkyl chain of the surfactants. An increase in the hydrophilicity of the alkyl sulfate molecule leads to a reduction of surface activity of both the surfactant and its cationic polymer complex [2]. It was found that in the case of hydrophilization of the sulfate "head" group of SDS by including a polyethylene oxide chain (4 to 10 units of ethylene oxide-EO) between the alkyl chain and the sulfate group there is a significant decrease in the sorptivity of the SDS -polyvinylpyrrolidone complex.[4] This effect is stronger the longer the oligo ethylene oxide chain, i. e., the more hydrophilic the head group, the weaker the interaction between SDS and the polymer [5].An interesting object for research of laws of interaction of ionic surfactants with the ionized polymers is a natural polysaccharide chitin, and especially its deacetylated derivative -chitosan. The presence in the chitosan molecule of hydroxyl and primary amino groups allows one to obtain new chitosan derivatives with surfactant properties that are promising for use in medicine, agriculture, food, and cosmetics industries [6,7]. Chitosan not containing alkyl groups shows practically no or very weak surface activity [8,9]. Introduction into the chitosan macromolecule of a small number of hydrophobic alkyl groups by alkylating amino groups or attaching a hydrophobic surfactant anion significantly increases the surface activity of the modified chitosan derivatives [10,11]. In [9,12] it is shown that the modification of chitosan by electrostatic attachment of an anionic surfactant (SDS) leads to the formation of surfactant-polyelectrolyte complexes with an unusually high surface activity. It is possible that both the head group and the hydrophobic chain of the surfactant are involved in the interaction with the polymer, wherein the hydrophobic interaction between the alkyl groups of the surfactant, which bonds ionically with the polymer chain of chitosan, occurs after electrostatic attachment of the first surfactant molecules to the polymer.In the study of t...