The electrochemical behavior of molybdenum oxide cathode materials with stoichiometries between and in nonaqueous lithium secondary cells are examined. Of the oxides , , , , and the greatest reversible capacity (>1 Li/Mo) after several deep discharge/charge cycles was exhibited by in cells with a electrolyte. Excepting , which gives a reversible capacity of >0.75 Li/Mo after 20 deep discharge/charge cycles, the reversible capacities of the other molybdenum oxides are considerably less than that of . The limiting reversible lithium capacity of 1.5 Li/Mo for was determined by treating with an n‐butyllithium solution and the lithium bronze formed with an solution. For an average cell voltage of 1.85V and a capacity of 1.5 Li/Mo, the theoretical energy density of (∼490 W‐hr/ kg) is comparable to that reported for and stoichiometric . The magnetic properties of both and the lithium bronze were also investigated and are discussed.