New crystalline salts of L-threonine, i.e. L-Thr.HCl, and L-Thr.HBr have been obtained from aqueous solution by slow evaporation technique. Infrared and Raman spectra of L-Thr.HCl and L-Thr.HBr were recorded and interpreted on the basis of crystal structure of L-Thr.HCl. The similarity of their IR and Raman spectra indicates similar structures. Nonlinear optical properties of the crystals were tested qualitatively by observation of second harmonic generation of Nd:YAG laser.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.