Platinum mineralization has been studied within two zoned clinopyroxenitedunite massifs of the Urals Platinum Belt. Within the Svetloborsky massif, platinum group minerals (PGM) occur directly in serpentinized dunite. The ore-forming system demonstrates the features of an early evolutionary stage: a significant portion of PtFe alloys belongs to ferroan platinum; native osmium is depleted in Ir; an isoferroplatinumosmium paragenesis is present. Within the Kamenushinsky massif, PGM are genetically related to chromitite and belong to the late-magmatic stage of the ore-forming system evolution: osmium and isoferroplatinum are rich in Ir; both isoferroplatinumosmium and isoferroplatinumiridium magmatic parageneses are present. The elevated Pt in the dunite of the Svetloborsky massif and in the chromitite of the Kamenushinsky massif is the result of two events: the primary-magmatic crystallization of PGM and later hydrothermal overprint.