The effects of mixing sodium alpha-sulphonated methyl ester derived from palm stearin salt ( α -SMEPS) with nonylphenol ethoxylate alcohol (NONIPOL) and polyoxyethylene (20) sorbitan monoester (TWEEN) in mixed micelles systems were studied as a function of their weight ratios. Changes in the critical micelle concentration (CMC) and surface tension were observed at different weight ratios of the mixed surfactant. Incorporating the nonionic surfactants into α-SMEPS solution changed the surface properties of the system by lowering the Kraft temperature and decreasing the foaming stability. The effects of these mixed anionic-nonionic surfactant were due to inter-action between the different hydrophobic and hydrophilic portions of the surfactants.