Alkenyl succinic anhydrides (ASA) are widely used in different areas, including additives for lubricants, intermediates in organic chemistry, corrosion inhibitors and paper sizing agents [1–3]. In the paper industry, oil-in-water (o/w) emulsions of ASA, are usually employed to impart water resistance to paper and paperboard since they confer hydrophobicity to cellulose fibers [3]. However, during the sizing process, ASA are in contact with water and are hydrolyzed to form CnSA (Scheme 1); the calcium or magnesium salts of CnSA cannot be effectively distributed over paper surfaces and form tacky deposits on papermaking equipment. Alternatives to solve this problem leads to the search of new methods to stabilize the emulsions formed with ASA [4–6]. In spite of the technological and economic importance of CnSA in the paper industry and the knowledge that it behaves as a surfactant, there have been, to the best of our knowledge, only a few studies regarding the physicochemical properties of the aggregates of CnSA in water. It has been reported [7,8] that the aqueous solutions of the acid form of C14SA and dipotassium salt of C12SA can form vesicles and small particles with diameters less than 7 m (in aqueous solutions at pH 5–6). In our laboratory, we observed that C12SA can self-associate (in buffer phosphate at pH = 7) at a very low concentration of surfactant (0.4 mM) [9]. This indicates that C12SA have a highly associative behavior, which is rather surprising in view of the double hydrophilic head and the relatively short tail. On the other hand, research have been performed using CnSA for studies of adhesion interactions [10] and a saturated derivative of C18SA was used in nucleation and control ofthe inorganic crystal growth in Langmuir experiments [11,12]. Since a key feature of CnSA is their ability to undergo selfassembly in water, a process in which factors such as surfactant molecular structure, surfactant concentration, and temperature dictate the type of aggregates formed; the aim of this work was to describe the aggregation behavior of disodium salt of 2-(2-decenyl) succinic acid C10SA (n = 10, Scheme 1) in alkaline aqueous media. The understanding of the physical chemical mechanism of aggregation and particularly the structural factors responsible for its surfactant efficiency despite its relatively short hydrophobic tail and a big hydrophilic head, will be important for the design of new materials.