The basic concept of small-angle X-ray and neutron scattering (SAXS, SANS) has been described by way of applications of polymer micelle systems. SAXS and SANS provide information on the size, shape and surface nanostructure of micelles. Based on model calculations and contrast variation in SANS, density inhomogeneity within the particle can be assessed. SAXS and SANS are highly useful for the study of surfactant micelle.