The spin polarization of photoelectrons emitted by alkali surfaces illuminated with monochromatic circularly polarized radiation has been observed. Maximum spin polarization of 4.5% is obtained with cesium at a wavelength of about 4500 A. Both maximum spin polarization and the wavelength of the maximum decrease monotonically with decreasing atomic number. The spin polarization is zero within experimental errors, in the case of solid sodium and lithium.