To provide a process for producing a lithium-containing composite oxide for a positive electrode for a lithium secondary battery, which is excellent in the volume capacity density, safety, charge and discharge cycle durability and low temperature characteristics.A process for producing a lithium-containing composite oxide represented by the formula Li.sub.pN.sub.xM.sub.mO.sub.zF.sub.a (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.ltoreq.p.ltoreq.1.2, 0.97.ltoreq.x<1.00, 0