We have established a characterization method of a 100 nm sized core-shell latexes composed of styrene-butadiene co-polymer. The core-shell structure was revealed by TEM observation of the latex film after modification with OsO4 vapor. Pyrolysis gas chromatography combined with mass spectrometry (Py-GC/MS) of the latexes showed the average chemical composition of the core-shell latexes. TOF-SIMS of the latex film gave the characteristic peak for styrene and butadiene. The peak intensities changed in accordance with the chemical composition of the latexes. Surface composition of the latex film, which corresponds to the composition of the shell part of the latexes, was estimated from this peak intensity ratio. From the combined analysis of Py-GC/MS and TOF-SIMS of the latexes, we successfully evaluated the chemical composition of both the core part and the shell part of latexes individually. As the results of characterization of some core-shell latex, it was revealed that the high degree of cross-linking is needed to synthesize the tailored core-shell latex. (c) 2006 Published by Elsevier B.V.