The extraction equilibrium study of Pt(IV) was carried out with Cyanex 923 and Cyanex 471X in toluene from hydrobromic acid media to investigate their extraction capacity, since they have different donor atoms, 'O' and 'S'. Their distribution equilibria were studied as a function of extractant concentration, diluents, hydrobromic acid concentration and the effect of temperature on extraction. Pt(IV) was quantitatively extracted with 0.1 mol dm(-3) Cyanex 923 in toluene from 5.0-8.0 mol dm(-3) HBr media and was stripped with 4.0 mol dm(-3) perchloric acid. However it was also quantitatively extracted with 0.1 mol dm(-3) Cyanex471X (with 0.1 mol dm(-3) SnCl2) in toluene from 6.0-8.0 mol dm(-3) HBr media and was stripped with 1.0 mol dm(-3) stabilized sodium thiosulfate solution at pH 9.0. The slope analysis method indicated metal complex species of 1:1 for Pt(IV) with Cyanex 923 and Cyanex 471X in toluene from HBr media. These methods were successfully applied to the analysis of platinum in real samples.