Polysiloxane films were prepared by plasma polymerization and dip coating. Upon these films PEG was grafted by conventional methods, and ethylene oxide by plasma activation. Before and after grafting the films were analyzed by contact angle and ESCA measurements as well as by FTIR-ATRspectroscopy and TOF-SIMS. Furthermore results of protein adsorption measurements are reported. The polysiloxane structures obtained by the plasma polymerization of HMDSO are rather similar to those ones yielded by dip coating. The two types of grafting applied on the polysiloxane substrates led to different structures of the grafted layers as was revealed by TOF-SIMS spectra.