A new composite material based on pyrolysed polysiloxane resins reinforced with basalt fibres will be developed. It will be manufactured in laboratory using the fibres both commercially available abroad and those developed in the Czech Republic using domestic raw materials. Light and electron microscopy will be used for investigation of the structure of fibrous reinforcement and the matrix. Mechanical and thermal mechanical properties will be studied in dependence on the type of reinforcement and processing parameters. The knowledge will be gathered for manufacturing the composites with properties suitable for application in various fields. Utilisation of theses composites as mechanically loaded structural parts at elevated temperatures can be expected.