Cu-xFe(3)O(4) nanocomposites with x = 5, 10, 15 and 20% have been obtained by powder metallurgy route starting from nanoscale magnetite and copper powders that were synthesized by co-precipitation. Both nanopowders and composite have been investigated for their structures, morphologies and physico-mechanical properties. Using high resolution microscopy methods, the structure of the initial powders and nanocomposite was investigated and the powder/grain size was evaluated. We demonstrated that the nanosized dimensions of both magnetite and copper powders obtained by co-precipitation has been preserved after sintering at 800 degrees C. It has been shown that both the copper matrix grains and the reinforcing Fe3O4 embedded in the matrix, have nanometric dimensions. Physico-mechanical properties of the nanocomposite have been studied in relation to crystalline structure and morphology. The electrical conductivity was determined, and the resistivity was calculated. Results showed the Cu-xFe(3)O(4) nanocomposites were situated at the boundary between conductors and semiconductors, i.e. nanocomposites with 15-20% Fe3O4 were electric conductors, and nanocomposites with content of 5% Fe3O4 were semiconductors. The electrical behavior of nanocomposites in alternating current showed that Cu-xFe(3)O(4) nanocomposites were good resistors too. (C) 2018 Elsevier B.V. All rights reserved.