Abstract. The Progress in designing of new advanced electro technical products requires that sometimes counteracting conductor’s material properties should be increased simultaneously, e.g. high electrical conductivity should be combined with high mechanical strength. Traditional high strength Cu-based conductors consist of Cu matrix, which contains a uniformly distributed small precipitates of intermetallic compounds or oxides. The required microstructure is usually formed by the doping of the initial Cu alloy by the combination of elements which would form the intermetallic compounds during the aging heat treatment at specific temperature range of 300 – 500 °C (Cu-Zr-Nb; Cu-Ni-Si; Cu-Cr-Zr alloys) or to form fine oxides through the process of internal oxidation (Cu-Al alloys). These submicron particles of oxides and intermetallic compounds altogether with increase of ultimate strength lead to substantial decrease of fatigue properties and to the significant decrease of the conductivity due to the practically unavoidable contamination of copper matrix by forming copper based solid solution. The paper describes the alternative approach to development of the advanced high strength high conductivity Cu-matrix composites with the application of the Cu-Nb microcomposites as a strengthening element. As an example the principally new design of composite Contact Wire for high speed of more than 400 km per hour. railways has been proposed to attain the record high combination of ultimate tensile strength (610 – 660 MPa) and high conductivity (more than 80% IACS). Composite conductor contains the bundles of nanostructured anomalously high strength Cu – Nb filamentary cores and outer layer made of low doped high conductivity Cu-Zr-Nb alloy with improved tribological properties. The microcomposite Contact Wire has very high fatigue properties due to filamentary architecture of microstructure of Cu-Nb strengthening component.  The proposed approach enabled to develop extremely fine wires with down to 25-30 µm with ultimate strength up to 1700 MPa and high flexibility. The examples of application of these fine wires in different advanced electro technical cables are given