[en] In connection with the potential domestic demand especially in the fields of industry and nuclear medicine, the separation of "1"3"7Cs from "2"3"5U fission process waste is to be of interest although its economic value could be a polemic. A preliminary study on the separation of "1"3"7Cs from the "2"3"5U fission process waste generated in the production of "9"9Mo in P.T. BATAN Teknologi, Serpong, was performed through experiments on "1"3"7Cs picking from sample solution of the radioactive fission waste (RFW). The presented study is aimed to gain experimental data supporting utilization of the matrix of silica gel-supported ferrocyanide complex salt for the separation of "1"3"7Cs from RFW. Subsequent step would be the recovery and purification of "1"3"7Cs as part of production technology of "1"3"7Cs. The RFW sample was batch-treated with the matrix of silica gel-supported ferrocyanide complex salt which was synthesized from silica gel, potassium hexacyanoferrate(II) and copper(II) chloride. The binding of radioisotopes in RFW on the matrix was observed by γ-spectrometry of the RFW solution before and during the treatment. The results showed that approximately 85% of "1"3"7Cs could be picked from the RFW sample into the matrix. Less amount of "9"5Zr and "9"5Nb was bound into the matrix. "1"0"3Ru was slightly bound into the matrix whereas "1"4"1"/"1"4"4Ce and "1"2"9"mTe were not. It was observed that by using 0.2 and 0.4 g of matrix for 10 ml of RFW, the amount of matrix influenced the binding quantity of "9"5Zr and "9"5Nb but not that of "1"3"7Cs. (author)