We present a study of the local magnetic properties of an iron/iron oxide nanostructured granular system by X-ray magnetic circular dichroism. The samples investigated consist of metallic iron (α-Fe) nanoparticles embedded in a nanocrystalline oxide matrix composed by both magnetite (Fe3O4) and maghemite (γ-Fe2O3). Samples were obtained by the inert gas condensation technique.Thanks to the chemical and site selectivity of XMCD, we were able to distinguish the magnetic contributions of the metallic core and of the two oxide phases present in the matrix and independently study their behaviour as a function of iron particle size, applied magnetic field, sample temperature and magnetization history.