  The type III seesaw mechanism for neutrino mass generation usually makes use
of at least two $Y = 0$, $SU(2)_L$ lepton triplets. We augment such a model
with a third triplet and a sterile neutrino, both of which are odd under a
conserved $\Z_2$ symmetry. With all new physics confined to the $\Z_2$-odd
sector, whose low energy manifestation is in some higher-dimensional operators,
a fermionic dark matter candidate is found to emerge. We identify the region of
the parameter space of the scenario, which is consistent with all constraints
from relic density and direct searches, and allows a wide range of masses for
the dark matter candidate.
