Weight reduction of machine parts and assemblies is an important issue in in many areas of modern industry is. Successful solution of this problem has few benefits - in short term perspective it will lower material and resource consumption, and in longterm perspective – lower cost of exploitation due to reduced weight. These aspects are the most important in automotive and aerospace industry, and also are of high priority in other industries. Many weight-reduced materials with open, close and mixed porosity were developed throughout the last decade. One of the approaches for the development of such materials is syntactic foams - materials with spherical hollow structures. Except the reduced weight this material has other benefits such as sound and mechanical absorption and mechanical damping. In the present work a byproduct of coal combustion at thermal and power plant - alumina-silica hollow spheres – cenospheres are exanimated. Chemical composition, phase composition, phase transition during thermal treatment, bulk density, macro and microstructure are investigated. Metallo-ceramic composites material with cenospheres, obtained by powder metallurgy route, has been tested. Improved relative density, compression strength, friction coefficient are the benefits of this material. It should be noted that cenosphere can be used for close porosity increased as weight reduction filler.