Cosmological data tells us that about 1/4th of our Universe
consists of dark matter. Theories beyond the Standard Model provide
candidates for this dark matter due to new discrete symmetries.
In this talk, I focus on the lightest neutralino of the Minimal
Supersymmetric Standard Model (MSSM) as dark matter candidate. In
particular, I discuss the neutralino properties and relic abundance in the
MSSM w/o CP violation, as well as requirements for collider tests of
neutralino dark matter.