  Seesaw mechanism provides a natural explanation of light neutrino masses
through suppression of heavy seesaw scale. In inverse seesaw models the seesaw
scale can be much lower than that in the usual seesaw models. If terms inducing
seesaw masses are further induced by loop corrections, the seesaw scale can be
lowered to be in the range probed by experiments at the LHC without fine
tuning. In this paper we construct models in which inverse seesaw neutrino
masses are generated at two loop level. These models also naturally have dark
matter candidates. Although the recent data from Xenon100 put stringent
constraint on the models, they can be consistent with data on neutrino masses,
mixing, dark matter relic density and direct detection. These models also have
some interesting experimental signatures for collider and flavor physics.
