We explore extensions of the SM where the dark matter mainly interacts with sterile neutrinos, which in turn generate masses for the active ones via the seesaw mechanism. We consider two prototype examples: in one of them, DM is charged under a global U(1)_B-L symmetry, spontaneously broken by a SM singlet scalar; in the other one, there is an exact dark symmetry. In both scenarios we analyze the parameter space region where the observed DM relic abundance is determined by the annihilation into sterile neutrinos, and we derive constraints from direct detection, collider probes and indirect searches.
