  We study production of dark matter (DM) in models with a non-standard
expansion history. We consider both freeze-out and freeze-in mechanisms for
producing the observed DM abundance in a model where the DM consists of scalar
singlet particles coupled to the Standard Model sector via the Higgs portal. We
show that a non-standard expansion phase can lead to a significant change in
the DM abundance and therefore to observational ramifications. For example, for
DM freeze-in the required portal coupling can be much larger, whereas for DM
freeze-out much smaller values become allowed. We evaluate the relevant
constraints and discuss prospects for direct detection of such DM.
