Crosslinked polyimide-poly(dimethylsiloxane)s with theoretical content of the siloxane phase up to 60 wt% were prepared. The starting materials were p-aminophenyltrimethoxysilane terminated polyamic acids with number average molecular weight of 10,000 g mol(-1), based on 4,4'-oxydiphthalic anhydride and 4,4'-oxydianiline and dimethoxydimethylsilane. The structure of the prepared polymeric materials was analyzed using Si-29 and C-13 NMR solid-state spectroscopy. Their thermal and mechanical properties, chemical resistance and density were evaluated. The influence of the basic catalysts employed (ammonium hydroxide) on the course of the reaction and properties of the materials was also studied.