The stability of the recently discovered CO-induced and self-organized CuPt surface alloy was explored at near ambient pressures of O 2 (200mbar) at room temperature, in a CO+H 2 mix (P tot =220mbar, 4% CO) from room temperature to 573K, as well as in a CO+H 2 O mix (P tot =17mbar, 50% CO) from room temperature to 673K. No indications of substantial changes in surface structure were observed under the latter conditions compared to CO alone whereas the O 2 oxidation resulted in CO removal and the build-up of an ultrathin CuO x -film. However, the oxidized CO/CuPt surface alloy could be regenerated by reducing the CuO x in 100mbar CO for 10min at room temperature. The results show, amongst others, the stability of the CuPt surface alloy in various environments containing CO and how a novel coinage/Pt-group bimetallic surface alloy catalyst induced by CO adsorption can be reactivated before use in applications such as electrochemistry at ambient temperatures.