  The electric and magnetic dipole moments of dyon fermions are calculated
within N=2 supersymmetric Yang-Mills theory including the theta-term. It is
found, in particular, that the gyroelectric ratio deviates from the canonical
value of 2 for the monopole fermion (n_m=1,n_e=0) in the case theta\not=0.
Then, applying the S-duality transformation to the result for the dyon
fermions, we obtain an explicit prediction for the electric dipole moment (EDM)
of the charged fermion (`electron'). It is thus seen that the approach
presented here provides a novel method for computing the EDM induced by the
theta-term.
