We report variational calculations of vibrational energies of CH4, CH3D, CH2D2, CHD3, and CD4 using the code "Multimode" and the ab initio force field of Lee and co-workers [Lee, T. J.; Martin, J. M. L.; Taylor, P. R. J. Chem. Phys. 1995, 102, 254], re-expressed using Morse variables in the stretch displacements. Comparisons are made with experimental energies for CH4 with this potential, and then small adjustments are made to the potential to improve agreement with experiment for CH4. Calculations for the isotopomers are done using the adjusted potential and compared with experiment. Additional vibrational energies and assignments not reported experimentally are also given for CH4 and the isotopomers. Exact rotational-Vibrational energies of CH4 are also reported for J = 1.