  We study the nuclear medium effects and nonisoscalarity correction in the
extraction of weak mixing angle sin$^2\theta_W$ using Paschos-Wolfenstein (PW)
relation. The calculations are performed for the iron nucleus. The results are
discussed along with the experimental result inferred by NuTeV collaboration.
The nuclear medium effects like Fermi motion, binding, shadowing and
antishadowing corrections and pion and rho meson cloud contributions have been
taken into account. Calculations have been performed in the local density
approximation using a relativistic nuclear spectral function which includes
nucleon correlations. These studies may be useful for the ongoing MINER$\nu$A
experiment as well as for the proposed NuSOnG experiment.
