The electrical and mechanical properties of composites made with Nicalon(R) NLM202 SiC (and Nextel(R) 440) woven fibres in a sol-gel prepared Nasicon matrix are reported. Local microhardness, interfacial shear stress and three point flexural strength have been determined and correlated to the conclusion of an X-ray microanalysis of the fibre-matrix interphases. The radio frequency (r.f.) to microwave conductivity of the composites has been measured and compared with that of their constituents (Nasicon matrix, SiC fibre) and with the direct current (d.c.) conductivity of extracted fibres.