Cu-Al2O3 composites are reported to have excellent resistance to high temperature annealing as well as high thermal and electrical conductivities. The uniform dispersion of nanometric ceramic particles in the metallic matrix provides unique characteristics to the material, enabling their application in high temperature and corrosive atmospheres. The special physico-chemical and mechanical properties are essentially dependent on the material`s microstructure, which in turn, will vary according to the composite preparation method. The main objectives of the present work are the introduction of a novel method for the preparation of Cu-Al2O3, Ni-Al2O3 nano- scale composites and their characterization. The preparation method is divided into two processes. In process 1, Al2O3 is formed in-situ by the addition of Al (NO3)3 solution to CuO powder, while in process 2, CuO or NiO and Al2O3 are formed in-situ from a water solution containing the dissolved nitrates of Cu or Ni and Al. Both the processes combine the advantages of chemical routes with that of in-situ processing, through the preferential H2 reduction of the CuO or NiO, contained in the mixture. The thermodynamics and kinetics studies presented have shown that the reductions of CuO to Cu and NiO to Ni are viable at a very low temperature (200-450oC). The Cu-Al2O3 (0.5, 1 and 5 wt%) specimens thus prepared have been examined by X-ray diffraction, scanning electron microscopy (SEM) and conventional, high resolution and scanning transmission electron microscopy (CTEM, HRTEM and STEM). The Cu crystals range from 50 to 300 nm for the Cu-Al2O3 (5 wt%)-process 1 and have an average grain size of 500/600 nm for the Cu-Al2O3 (0,5 and 1 wt%)-process 1, while the Al2O3 particles range from 10 to 60/70 nm in all cases. The Cu- Al2O3 (0.5, 1 and 5 %Peso)-process 2 composites are composed of a homogeneous dispersion of Cu, Al and O. Composites prepared by both the processes, have exhibited the formation of a third phase, which is suggested to be CuAlO2 and/or CuAl2O4. The Ni-Al2O3 (0.5 wt%) nano-scale composites have also been successfully prepared through process 2 and their characterization revealed a microstructure similar to that of the Cu-Al2O3 samples. By applying process 2, it has also been possible to co-form CuO and NiO. This co-formed oxide mixture has been reduced in H2 atmosphere at a low temperature of 400oC to produce a homogeneous nano-powder of a Cu-Ni (50 at%) alloy.