A process for producing propylene oxide comprising reacting propene with hydrogen peroxide in the presence of a catalyst to give a mixture (G1) comprising propylene oxide, unreacted propene, and oxygen; separating propylene oxide from mixture (G1) to give a mixture (GII) comprising propene and oxygen; and adding hydrogen to mixture (GII) and reducing the oxygen comprised in mixture (GII) at least partially by reaction with hydrogen in the presence of a catalyst comprising copper in elemental and/or oxidic form on a support, wherein copper is present on the support in an amount of 30 to 80 wt.-% based on the whole catalyst and calculated as CuO.