  We show that in a class of universal extra dimension (UED) models that solves
both the neutrino mass and proton decay problems using low scale left-right
symmetry, the dark matter of the Universe consists of an admixture of KK photon
and KK right-handed neutrinos. We present a full calculation of the dark matter
density in these models taking into account the co-annihilation effects due to
near by states such as the scalar partner of the KK photon as well as fermion
states near the right-handed KK neutrino. Using the value of the relic CDM
density, we obtain upper limits on $R^{-1}$ of about 400-650 GeV and
$M_{Z'}\leq 1.5$ TeV, both being accessible to LHC. For a region in this
parameter space where the KK right-handed neutrino contributes significantly to
the total relic density of dark matter, we obtain a lower bound on the dark
matter-nucleon scattering cross section of $10^{-44}$ cm$^2$, which can be
probed by the next round of dark matter search experiments.
