In this work, we present a study focused on the effect of partial substitution of Co by Fe on structure and magnetic properties of nanocrystalline Pr 2 Co 7 . These compounds were synthesized by mechanical alloying and to correlate their properties with microstructural evolution, a multi-scale study by: X-ray diffraction (XRD), transmission electron microscopy, and magnetization was carried out. The Rietveld analysis of XRD diagrams shows that Pr 2 Co 7Àx Fe x , annealed at 973 K, mainly adopt a hexagonal Ce 2 Ni 7 type structure with P6 3 /mmc space group. These pseudo-ternary compounds exhibit more interesting magnetic properties than the binary Pr 2 Co 7 compounds.A systematic study of the intrinsic magnetic properties of these alloys shows that the substitution leads to enhancement of the Curie temperatures (T C ) by 26% for a Fe content equal to 0.5. This increase is due to the electronic as well as the magnetovolume effects. In addition, the study of extrinsic magnetic properties of the Pr 2 Co 6.5 Fe 0.5 compound has revealed the existence of a large coercive field H c , and a high remanent magnetization M r . Our results show that in these alloys, iron in solid solution has a strong effect on hardness and ordering temperature, which is particularly promising for permanent magnet applications.