Valence band spectra from similar polymers frequently show significant differences in appearance. Recent improvements in x-ray photoelectron spectroscopy instrumentation allow for valence band (VB) spectra with good signal to noise to be rapidly acquired. This study utilizes the VB region for the quantitative determination of the surface composition of several binary polymer systems using multiple linear regression. The systems evaluated include : poly(vinyl chloride)/poly(methylmethacrylate) blends which phase separate, chemically derivatized poly(vinyl methyl ketone), miscible polybutylmethacrylate isomers used in a study of liquid crystal alignment, and acrylate copolymers whose surface composition has been quantified using time-of-flight secondary ion mass spectrometry. For systems in which comparisons to core level spectra are possible, good agreement is found between quantification of core level and valence band spectra.