To provide refrigerating machine compositions which exhibit good lubricity and a high viscosity index even under a refrigerant having carbon dioxide as the major component and further, to provide refrigerating machine compositions which excel in stability and lubricity in the atmosphere of a carbon dioxide in the supercritical state while maintaining said characteristic features and, in addition, are usable over a long period of time.

Refrigerating machine oil compositions for a carbon dioxide refrigerant have, as the major components, (A) more than 40 wt.% to not more than 99.1 wt.% polyvinyl ether having a kinematic viscosity at 100°C of 3-50 mm2/s and (B) not less than 0.1 wt.% to less than 40 wt.% polyoxyalkylene glycol having a kinematic viscosity at 100°C of 3-50 mm2/s.