A series of Mn_xCu_1–xFe₂O₄ (x = 0.5, 0.6, 0.7) nanoferrites were prepared by sol-gel auto combustion method. The XRD patterns revealed cubic spinel structure of ferrite systems. Secondary phases of α-Fe₂O₃ are found also with the ferrite phase. The lattice parameter and crystallite size are found to be in the range (8.314–8.389Å) and (12.1–14.5nm). The secondary phases seem to be influence the structural properties of present ferrite systems. Mössbauer spectra showed that each composition have two sextets and two doublets. Core-shell model was well suited to explain the magnetic behaviour of present ferrite systems. The hyperfine fields at A and B sites are influenced by the cation redistribution and predominantly due to Cu²⁺ ions in the spinel structure. In the present study results of structural and Mössbauer studies are reported.