Abstract: The isotopes of zirconium can be partially or completely separated by loading an aqueous solution of an ionic compound of zirconium onto a cationic exchange resin which serves as the stationary phase of a chromatograph, eluting the compound with an aqueous acid and collecting distinct elution volumes representative of each isotope. In a preferred embodiment, the eluant is a strong mineral acid, such as hydrochloric acid and the chromatograph is of a type, such as a continuous annular chromatograph that it can be operated in a continuous, steady state manner.