In this work, we report a theoretical vibrational study of thiophene methyl derivatives. The vibrational spectra of 2-methylthiophene and 3-methylthiophene were evaluated using ab initio methods at the RHF/6-31G * * level. A set of suitable scaling factors was used to obtain scaled quantum mechanical force fields for both molecules. The optimized structural and vibrational parameters are in good agreement with the experimental results.