The nature and identity of the dark matter of the Universe is one of the most challenging problems facing modern cosmology. Only ~5% of the energy density of the Universe can be associated with known forms of matter. In this talk, the observational evidence and theoretical motivation for dark matter will be presented. Problems for baryonic and neutrino dark matter imply the necessity to search beyond the standard model for dark matter candidates. Emphasis is placed on the prospects for supersymmetric dark matter.