The distribution of hafnium(IV) and scandium(III) sulphate complexes between an anion-exchange resin in the sulphate form, and sulphuric acid solutions has been studied. Equations giving the variation of the distribution ratio with the ligand concentration have been established for both metals ; the sulphate complexes formed in solution are discussed. For hafnium, the optimal conditions for adsorption involve sulphate concentrations of 2·10⁻²–10⁻¹M at pH 3.5–4.5 ; for elution 2–4 N sulphuric acid should be used. For scandium, optimal adsorption is obtained with 10⁻¹M sulphate at pH3, and ⩾0.4 N sulphuric acid is best for elution.