An agglomeration-leaching process was evaluated to decontaminate Co-60 and Cs-137 from radioactive soils. Radioactive soils were screened based on the particle size of 0.075 mm. The soils with particle size of less than 0.075 mm were agglomerated by using a 2 wt% Na2SiO3 which had been predetermined to be an optimum reagent for an agglomeration. The agglomerated soils were mixed with the other soils with particle size bigger than 0.075 mm for leaching tests. Several leaching solutions were evaluated for their leaching performances for Co-60 and Cs-137 from simulated soil wastes, and the 0.1 M HCl solution was shown to be the most effective one. Leaching tests for radioactive soils in a column showed that the radioactive soils contaminated with Co-60 and Cs-137 radionuclides could be decontaminated down to the potential release criteria (~100 Bq/kg) by using the appropriate conditions of an agglomeration- leaching process.