  We discuss the polar Kerr effect (PKE) in a chiral p-wave (p_x+i p_y-wave)
superconductor. It is found that the off-diagonal component of a
current-current correlation function is induced by impurity scattering in the
chiral p-wave condensate, and a nonzero Hall conductivity is obtained using the
Kubo formula. We estimate the Kerr rotation angle by using this
impurity-induced Hall conductivity and compare it with experimental results
[Jing Xia et al., Phys. Rev. Lett. 97, 167002 (2006)].
