BEDT-TTF is the donor of the highest T-c organic superconductors. Isotopic shift experiments support an. electron-phonon coupling mechanism for the superconductivity. However, the vibrational levels have been only partially observed and assigned, making testing of this mechanism difficult. In order to provide a complete consistent description of all vibrational levels, we carried out Hartree-Fock calculations (6-31G** basis set) to obtain the Hessians and fundamental vibrational frequencies of BEDT-TTF and BEDT-TTF+. With these Hessians and;available experimental frequencies, we used Hessian-biased methods to develop the MSX force fields for the neutral and cation BEDT-TTF molecules. Comparison of the calculated frequencies with the available experimental frequencies for the neutral and cation BEDT-TTF molecule shows good agreement.