Polyetherimide (PEI), an amorphous thermoplastic material, is a promising candidate for wide applications due to its high heat stability and its biocompatibility in human tissues. In the present paper, PEI (4 wt%) is added to SiO2 inorganic matrix in order to obtain a novel composite biomaterial through sol‐gel route. Structural characterization by means of Fourier Transform Infrared Spectroscopy (FTIR) confirmed, through hydrogen bond interactions, the presence of both organic and inorganic components in the structure. Concerning the compatibility in the biological systems, a study of antibacterial properties is carried out, analyzing the effect of SiO2/PEI composite on Escherichia coli (gram‐negative) and Enterococcus faecalis (gram‐positive).