The article encompasses new data on geochemistry of dunites forming the Svetloborsky and Nizhnetagilsky ultramafic massifs of the Ural Platinum Belt. Petrogenesis of both massifs is discussed based on their interpretation. The research establishes that both massifs are petro-chemical equivalents of alpinotype complexes and zonal massifs, but at the same time they have their own particularities. Thus, dunites of the Svetloborsky massif are enriched in almost all rare elements compared to the Nizhnetagilsky massif that may be caused by their redistribution during subsequent processes due to intrusion of mafic dykes.