Micellization behavior of sodium dodecyl sulfate (SDS) and its mixture with polyethylene oxide (PEO) are investigated using surface tension and light scattering techniques. The data are presented and interpreted in a novel way, which provides more and reliable information about the interaction of the components. The concentration of SDS corresponding to the initiation of interaction with PEO (T-1) and the saturation point (T-3) are well identified in this way. It has been observed that the concentration span between T-1 and T-3 is not much affected by the amount of PEO added. The detail investigation of data concludes that SDS and PEO interactions are in one to one ratio at molecular level and CMC decreases with the addition of salt to the system and the micelles become more compact. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 1444-1448, 2009