The molecular geometry and vibrational frequencies of the 3-(6-benzoyl-5-chloro-2-benzoxazolinon-3-yl) propanoic acid in the ground state has been calculated using the Hartree-Fock and density functional using Becke's three-parameter hybrid method with the Lee, Yang, and Parr correlation functional (B3LYP) methods with 6-31G(d) basis set. The theoretical vibrational spectra of the title compound were interpreted by means of potential energy distributions (PEDs) using VEDA 4 program. The calculated geometrical parameters and harmonic vibrations are in a very good agreement with experimental data. With the aid of this modem technique we were able to complete the assignment of the vibrational spectra of the title compound. (C) 2006 Elsevier B.V. All rights reserved.