Opitcal magnetization of a metal single crystal is observed for the first time by spin polarized photoemission. The (100) -surface of a tungsten crystal was irradiated by circularly polarized light and the spin polarization of the emitted photoelectrons was measured for light energies 1.5 eV?hν?5.6 eV. The polarization reaches a maximum of 8% and its sign changes as function of photon energy. In order to obtain photoemission from transitions between the spd-hybridized conduction bands, the work function had to be lowered by depositing cesium onto the surface. The successful outcome of this measurement opens the prospect to develop a new, spin-sensitive tool to explore electronic band structures.