Polyimide/silica hybrids were prepared by a sol-gel process and were evaluated in terms of curing behaviour, morphology and mechanical properties at different temperatures. The spectroscopic examinations showed that the presence of inorganic phase accelerates both the removal of the solvent and the concomitant imidization reaction. Two types of morphology for the silica phase were obtained by tailoring the composition of the precursor solution mixture. The mechanical properties were found to be strongly dependent on the system morphology. The largest increase in rigidity and strength properties were achieved when the two phases were co-continuous. Furthermore, these nanocomposites exhibited better mechanical properties also at high temperatures, thus extending the possible service temperature range of the polyimides. (C) 2003 Elsevier Ltd. All rights reserved.