  We investigate the viability of having dark matter in the minimal left-right
symmetric theory. We find the lightest right-handed neutrino with a mass around
keV as the only viable candidate consistent with a TeV scale of left-right
symmetry. In order to account for the correct relic density with such low
scales, the thermal overproduction of the dark matter in the early universe is
compensated by a sufficient late entropy production due to late decay of
heavier right-handed neutrinos. We point out that the presence of the
right-handed charge-current interactions, operative around the QCD phase
transition, has a crucial impact on the amount of dilution, as does the nature
of the phase transition itself. A careful numerical study, employing the
Boltzmann equations, reveals the existence of a narrow window for the
right-handed gauge boson mass, possibly within the reach of LHC (in
disagreement with a previous study). We also elaborate on a variety of
astrophysical, cosmological and low energy constraints on this scenario.
