The aim of the present study was to elucidate the inhibition efficiency of molybdate ions towards the AZ31-xLi (x = 4, 8, 12) Mg alloys depending on the amount of the molybdate inhibitor in the corrosive medium and Li in the AZ31 Mg alloy. To do so, a set of classical electrochemical techniques, coupled with g-DEIS monitoring and spectroscopic surface analyses, has been used and the inhibition mechanism of AZ31-xLi (x = 4, 8, 12) Mg alloys by soluble molybdates has been proposed. A detailed examination of corrosion processes and inhibition efficiency of molybdates towards the AZ31 alloy without Li addition has been reported in our previous publication . Therefore, this alloy is not examined in the present contribution, and data from cab be used as a reference.