  We study rotating compact stars that are mixtures of the ordinary nuclear
matter in a neutron star and fermionic dark matter. After deriving equations
describing a slowly rotating system made up of an arbitrary number of perfect
fluids, we specialize to the two-fluid case, where the first fluid describes
ordinary matter and the second fluid describes dark matter. Electromagnetic
observations of the moment of inertia and angular momentum directly probe
ordinary matter and not dark matter. Upon taking this into account, we show
that the I-Love-Q relations for dark matter admixed neutrons stars can deviate
significantly from the standard single-fluid relationships.
