Studies of the mechanical properties of nanomaterials are probably those which experimental results bring most controversies. So far, mechanisms of plasticity and low temperature superplastic behaviour are actually unclear [1]. As for most properties, scattering of results comes from the strong dependence of properties with synthesis and processing routes. Additionally, investigations of mechanical properties suffer from a lack of bulk large dimension and fully dense nanostructured specimens, for reliable testing to be carried out. In order to overcome the unstable character of nanostructures, related to an enhanced reactivity, diffusivity and grain growth, outstanding astuteness are used in synthesis and processing for grain refinement and then for keeping these grains in the nanometer range. Among main processing routes which produce large specimens: (i) the crystallisation from amorphous phases [2], (ii) the mechanically activated self-heat sustaining reaction (MA, SHS) [3], (iii) the mechanical alloying followed by compaction and sintering [4], (iv) the equal channel angular (ECA) processing [5] and (v) the compaction and sintering of nanopowders produced by evaporation-condensation techniques [6]. Comparison between various nanomaterials are not straightforward, since synthesis are very different and bring structural variations, mainly: for (i), (ii) local structural heterogeneity and chemical gradient, (i)-(iv) lattice strain, (ii), (iii) impurities, (ii), (iii), (v) residual porosity, (iv) grain size not less than 100 nm and (v) small size specimens. However, all these nanostructures reveal unusual and high mechanical performances that justify the fundamental investigations and let predict many applications. For some years, metallic nanocrystalline powders are synthesised by cryo-melting, which consists of condensing a metal vapour within a cryogenic medium. The technique produces loose powders of spherical particles in the size range of 30–100 nm. It is featured by a moderate production yield that allows the fabrication of fully dense bulk and large size nanostructured specimens [7]. This article reports on the fabrication and the mechanical behaviour of nanostructured copper (nCu) materials, obtained from nanocrystalline Cu by compaction, sintering and extrusion. Synthesis and characterisation of nanopowders are fully documented in [8]. Fabrication of bulk nanostructured copper is briefly overviewed here after. The mechanical behaviour is reported and discussed with respect to literature data and comparison with microcrystalline copper extruded in the same way.