An analysis of the radial structure of carboxylated latex particles by small-angle X-ray scattering (SAXS) is given. The latex was prepared by a batch emulsion polymerization of methyl methacrylate and methacrylic acid. The analysis of the SAXS intensities leads to the conclusion that the particles of number-average diameter 90.8 nm exhibit a pronounced core-shell structure, i.e., practically all the carboxyl groups are located within a shell of 13.6 nm thickness.