To provide a process for a lithium-containing composite oxide for a positive electrode for a lithium secondary battery, which has a large volume capacity density and high safety, and is excellent in the charge and discharge cyclic durability and low temperature characteristics. A process for producing a lithium-containing composite oxide represented by the formula LipNxMyOzFa (wherein N is at least one element selected from the group consisting of Co, Mn and Ni, M is at least one element selected from the group consisting of Al, alkaline earth metal elements and transition metal elements other than N, 0.9≦p≦1.2, 0.95≦x≦2.00, 0≦y≦0.05, 1.9≦z≦4.2 and 0≦a≦0.05), which comprises firing a mixture of a lithium source, an N element source, an M element source and if necessary, a fluorine source, characterized in that an aqueous solution having an M element source dissolved therein is mixed with an N element source powder or its pulverized product to form a slurry; if necessary after being pulverized, the slurry is dried for granulation to obtain a granulated product, which is mixed with a lithium source powder and if necessary, a fluorine source powder to obtain a mixture; and the mixture is fired at from 700 to 1,100° C. in an oxygen-containing atmosphere.