Process for the recovery of transition metal from spent lithium ion batteries containing nickel, wherein said process comprises the steps of (a) heating a lithium containing transition metal oxide material to a temperature in the range of from 200 to 900° C. in the presence of H2, (b) treatment of the product obtained in step (a) with an aqueous medium, (c) solid-solid separation for the removal of Ni from the solid residue of step (b), (d) recovery of Li as hydroxide or salt from the solution obtained in step (b), (e) extraction of Ni and, if applicable, Co from the solid Ni-concentrate obtained in step (c).