As described in a previous paper (Mareš and John in J Radioanal Nucl Chem, 2019. https://doi.org/10.1007/s10967-019-06456-2 ), isotopically manipulated molybdenum used as an inert matrix in advanced types of nuclear fuels should be recycled. This study aimed to demonstrate the possibility of removing caesium from concentrated molybdenum solutions resulting from the proposed molybdenum reprocessing procedure. The commercially available DOWEX 50W, Amberjet 1000H, Crystalline Ionsiv IE910 and IE 911 exchangers as well as four in-house prepared hexacyanoferrates (Nickel, Potassium-nickel, Potassium-cooper and Potassium-cobalt) were tested in batch and column experiments. The results revealed that KNiFC-PAN resin is the most promising ion exchanger for caesium separation from a slightly alkaline (pH 9.1) ammonium molybdate solution.