Nanocrystalline Fe 90 Ni 10 alloys were synthesized by mechanical alloying, starting from a powder mixture of elemental Fe and Ni. The phase evolution and magnetic properties were investigated, as a function of milling time, using the X-ray diffraction (XRD), the vibrating sample magnetometer (VSM), and the 57 Fe Mössbauer spectroscopy. From XRD results, we concluded the formation, after 13 h of milling, of a disordered phase α -Fe(Ni) (bcc). It has been shown that the increase of milling time decreases the crystallites size and increases the microstrains and the lattice parameter. When the crystallites size decreases, the coercive field, H c , decreases first, then increases and finally reaches a constant value of about 26 Oe. During the periode of the alloy formation, the saturation magnetization, M s , increases with decreasing crystallite size and reaches the highest value of 212 emu/g after 27 h of milling, then, M s remains constant up to 48 h of milling. The adjustment of Mössbauer spectra revealed that the fraction of the (bcc) α -Fe(Ni) phase increased with milling time. After 13 h of milling, only the (bcc) α -Fe(Ni) phase is observed.