Magnesium-substituted nickel–chrome ferrites have been studied using X-ray diffraction and Mössbauer spectroscopy. A single cubic spinel phase was obtained in the range 0.0 ≤ x ≤ 0.4. The lattice parameter was found to decrease with the increase of Mg concentration. The Mössbauer spectra measured at 295 and 78 K of all samples showed magnetic patterns interpreted in term of the tetrahedral and octahedral sites occupancies. The magnetic hyperfine field of both sites decrease with the increase of the Mg concentration. The magnetic properties as a function of the Mg concentration have been explained on the basis of the cation distribution among the two crystallographic sites driven from the Mössbauer measurements.