Synchrotron radiation excited photoemission spectroscopy studies have been carried out on 5-methyl-2-mercaptobenzoxazole adsorbed on Cu2S surface. This paper reports one of the first applications of this technique in the field of mineral processing investigations. The use of synchrotron photon source permits investigation of the real first stage of adsorption, because of the high surface sensitivity. S 2p and O 1s spectra for the Cu2S surface after immersion in 5-methyl-2-mercaptobenzoxazole solutions at different solution concentrations (10(-6) M and 10(-5) M) and different contact times (1 min and 15 min), together with those for UHV-cleaved Cu2S at205 eV and 555 eV photon energies an presented and discussed.