The very efficient hydrogenation of CO2 in the presence of ethylene oxide has been catalyzed by soluble ruthenium complexes to obtain CO and ethylene glycol in good yields; over 70% of the CO2 was converted into these products at 140-180 degrees C, indicating that the reaction does not suffer from thermodynamic or kinetic restrictions at these reaction temperatures. The reaction mechanism may include CO2 insertion into ethylene oxide to form ethylene carbonate in the first step, followed by its hydrogenation. Therefore, ethylene carbonate can be regarded as an activated CO2 with respect to its hydrogenation.