The normal mode frequencies and corresponding vibrational assignments of trimethylsilylcyanide are examined theoretically using the gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of eight types of motion (Si–C stretch, CN stretch, C–H stretch, C–Si–C bend, Si–CN bend, H–C–H bend, CH 3 rock, and CH 3 twist) utilizing the C 3v symmetry of the molecule. Calculations were performed at the Hartree–Fock, DFT (B3LYP), and MP2 levels of theory using the standard 6-311G** basis. Theoretical results were successfully compared against available experimental data.