  We present non-perturbative renormalization constants of fermionic bilinears
on the lattice in the quenched approximation at beta=6.1 using an overlap
fermion action with hypercubic(HYP)-blocked links. We consider the effects of
the exact zero modes of the Dirac operator and find they are important in
calculating the renormalization constants of the scalar and pseudoscalar
density. The results are given in the RI' and MS bar schemes and compared to
the perturbative calculations.
