The adsorption of a double-chained surfactant, sodium bis(2-ethylhexyl) sulfosuccinate (aerosol OT), and poly(vinylpyrrolidone) (PVP) from their mixed aqueous solutions on alumina has been studied by measuring adsorbed amount, zeta-potential, ESR, and dispersion stability. The adsorption of PVP was enhanced by the presence of aerosol OT due to formation of a surface complex of PVP and aerosol OT, and this enhancement is proportional to the feed concentration of PVP. The conformation of PVP adsorbed was estimated using a spin-labeled polymer, and it changed from loops and tails to trains with increasing aerosol OT concentration. The portion of train segments becomes smaller with increasing feed concentration of PVP. The addition of aerosol OT enhances remarkably the adsorption of PVP in comparison with a single-chained anionic surfactant.