  The two-loop contribution to the electric dipole moment (EDM) and the chromo
electric dipole moment (CEDM) of an arbitrary fermion f induced by the most
general renormalizable tbW coupling with complex left- and right-handed
components (a_L and a_R) is calculated. The analytical expressions are
numerically evaluated and the current experimental constraints on the electron,
neutron and mercury atom EDMs are used to obtain a bound on the complex phase
Im(a^*_La_R). It is found that the most stringent constraint, Im(a^*_La_R)<2.33
X 10^{-2}, arises from the neutron EDM.
