Backward scattering in-phase dual circular polarization (DCPI) Raman optical activity (ROA) spectra of L-alanine, L-alanine-2d(1), L-alanine-3,3,3-d(3) in H2O and D2O solution in the 800-1700 cm(-1) frequency region are presented. Ab initio calculations of normal modes and Raman and ROA intensities have been carried out with a 6-31G* basis set and inclusion of a solvent reaction field for stabilization of the zwitterionic forms. Excellent agreement is found between experiment and calculation for both Raman and ROA spectra. However, some discrepancies are noticed between the experimental and theoretical ROA intensities for alanine-2d(1).