The scaled phase FTIR and FT-Raman spectra of 1,5-dimethylnaphthalene(DMN) has been recorded in the region 4000-400 cm-1 and 4000-50 cm-1, respectively. The fundamental vibrational wavenumbers and intensities of vibrational bands are evaluated with the aid of normal coordinate analysis based on density functional theory (DFT) using the standard B3LYP/6-31G** method and basis set combination with scaled quantum mechanical force field. The Infrared and Raman spectra are also predicted from the calculated intensities. Comparison of simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes.