  We present renormalization factors for the bilinear operators obtained using
the non-perturbative renormalization method (NPR) in the RI-MOM scheme with
improved staggered fermions on the MILC asqtad lattices ($N_f = 2+1$). We use
the MILC coarse ensembles with $20^3 \times 64$ geometry and $am_{\ell}/am_s =
0.01/0.05$. We obtain the wave function renormalization factor $Z_q$ from the
conserved vector current and the mass renormalization factor $Z_m$ from the
scalar bilinear operator. We also present preliminary results of
renormalization factors for other bilinear operators.
