Progress in third-generation synchrotron radiation facilities has made possible, nowadays, the determination of induced spin and orbital magnetic moments of 5d transition metal elements via the element-specific X-ray magnetic circular dichroism technique. In this work, recent results on the magnetic moments of Pt in Co -based alloys and multilayers are briefly reviewed. The magnetic moment carried by the 5d electrons of Pt in these systems ranges between 0.2 and 0.7μ B /atom. The ratio of orbital μ L to spin μS magnetic moment is found to be in the range 0.15–0.25. Finally, a method is described for the determination of Pt magnetic moment in lattices other than the fcc lattice, which is the thermodynamically stable crystallographic structure of bulk Pt .