Enzyme electrodes were fabricated by entrapping enzymes in the polymethylsiloxane(PMSO) matrix prepared by sol-gel method. The GOD-immobilized PMSO/Pt electrodes showed reproducible current signals to glucose and the linearly responding concentration range of glucose was up to 45mM. The R values (H₂O/MTMS molar ratio) employed in the hydrolysis of MTMS had the most significant effects on the sensing properties of the resulting enzyme electrodes. With the R value of lower than the stoichiometric value(3.0), the enzyme electrodes showed better linearity than those for R> 3.0. But the storage stability was better for R>3.0. FT-IR data indicated that the degree of condensation of the siloxane group was proportional to the R value. In case of R≤3.0, the linearity and response time increased with a reduction of the current signals. From the results, it was interpreted that when R≤3.0 the condensation reaction is not completed, thus the reaction proceeds further during the storage. As a result of the progressive condensation reaction the matrices become rigider and less porous, i.e. the diffusion of glucose becomes more difficult, resulting in a longer response time and smaller current signals. Similarly, the alcohol oxidase-immobilized PMSO/Pt electrodes were prepared, which showed reproducible current signals to methanol and ethanol.