  We study the influence of impurities in graphene described by a scattering
rate $\Gamma$ on the Casimir interaction between graphene and an ideal
conductor or between two identical sheets of graphene at zero temperature and
chemical potential. To this end, we compute the polarization tensor of
quasiparticles in graphene and corresponding conductivities for TE and TM
channels. The Casimir energy density is evaluated with the help of the Lifshitz
formula. We find that depending on the value of mass gap parameter the presence
of $\Gamma$ may lead to a slight damping or to a considerable enhancement of
the Casimir interaction.
