The electron affinity and ionization potential for the CH3 radical have been calculated at high levels of ab initio molecular orbital theory. The best values are obtained by extrapolating CCSD(T)/aug-cc-pVxZ values where x = D, T, Q to the complete basis set limit. Zero-point energies were calculated at the CCSD(T)/aug-cc-pVTZ level and scaled to appropriate experimental values. The calculated values are EA(CH3) = 1.64 +/- 0.3 kcal/mol as compared to the experimental value of 1.84 +/- 0.69 kcal/mol and IP(CH3) = 9.837 +/- 0.01 eV as compared to the experimental value of 9.843 +/- 0.001 eV. The theoretical values included estimates of relativistic and core/valence correlation effects.