Hydrophilic poly(2-hydroxyethyl methacrylate) has been accepted as a biocompatible material for medical applications. Some of its relatively poor physical property are still remained as problems to be improved. In order to improve its physical properly, new copolymers of 2-hydroxyethyl methacrylate (HEMA) with silane monomers have been developed and synthesized. The silane monomers are γ-methacryloxypropyl triethyl silane (MPTS) and γ-methacryloxypropyl methyl bistrimethyl siloxysilane (MPMBSS). The compositions of unreacted monomers in the copolymers were separated and determined by the intensity of each peak by gas chromatographic analysis. The monomer reactivity ratios determined by the Kelen-T d s method are as follows. r_l = 0.80 and r₂ = 0.71 for poly (HEMA-co-MPTS), r_l = 1.22 and r₂ = 0.21 for poly (HEMA-co-MPMBSS). The tendency of alternating copolymerization and the relative reactivity of MPTS and MPMBSS with HEMA were investigated. The Q and e values are also calculated by the Alfrey-Price equation. The synthesized monomers and copolymers were identified by infrared spectroscopy and nuclear magnetic resonance spectroscopy. The thermal properties of the copolymers were also measured by thermogravimetry and differential scanning calorimetry.