A system combining polarization modulation with digital synchronous detection has been adapted for Raman spectroscopy. The apparatus permits an accurate determination of the polarization of scattered light and offers a number of other advantages over conventional measurements of Raman spectra. Brief derivations of formulas useful for analyzing data are given. The resolution of this apparatus is 87% of the theoretical maximum. The utility of the system is demonstrated by presenting the modulation Raman spectrum of sodium chlorate.