Abstract: A chemical process for treating an aged 252Cf spontaneous fission neutron source in which the initial amount of 252Cf is about five micrograms is presented in this paper. It consists of the following principal steps: mechanical decladding, dissolution of Pd-Cf2O3 ceramic wire, removing of Pd by anion exchange and separation of Cf from Cm by HDEHP extraction chromatography.Experimental results indicate that the yield of recovery of 252Cf is more than 90 % and no contamination of other α-andγ-emitters in Cf product could be found by α-and γ-spectrometry measurements.