An oxygen storage material comprising cerium oxide and at least one second oxide of a metal M.sup.1 is disclosed as well as a process for manufacturing the material and the use of this material in an exhaust gas cleaning catalyst. In a preferred embodiment the oxygen storage material comprises particles from a Ce/M.sup.1 mixed oxide solid solution coated with an oxide of another metal M.sup.2. Metal M.sup.1 e.g. can be calcium or zirconium while metal M.sup.2 most preferably is aluminum.