Proposed is a method for the preparation of a powder of lanthanum manganite having excellent flowability with an angle of repose not exceeding 45.degree.. Different from conventional methods for the preparation of lanthanum manganite powder by the calcination of a powder blend of thermally decomposable compounds of lanthanum and manganese or by the precipitation of a composite carbonate of lanthanum and manganese with addition of an aqueous solution of ammonium carbonate to an aqueous solution of lanthanum and manganese compounds followed by calcination of the composite carbonate, the invention proposes to precipitate the composite carbonate by the addition of ammonium carbonate in a particulate form to the aqueous solution of lanthanum and manganese compounds followed by calcination of the composite carbonate.