Process for recovering copper sulphide and optionally molybdenum sulphide from a copper bearing ore by froth flotation includes crushing said ore, mixing the obtained ground powder with at least a collector and water, aerating the slurry, and removing and concentrating the mineral froth formed at the surface of the bath, wherein the collector comprises a thioglycolic acid derivate having the following formula: wherein R1 is N or O, and R2 is an alkyl group having 2 to 12 carbon atoms.