A new bioenzymatic glucose biosensor for selective and sensitive detection of glucose was developed by the immobilization of glucose oxidase (GOD) onto selenium nanoparticle-mesoporous silica composite (MCM-41) matrix and then prepared as a carbon paste electrode (CPE). Cyclic voltammetry was employed to probe the catalytic behavior of the biosensor. A linear calibration plot is obtained over a wide concentration range of glucose from 1 x 10(-5) to 2 x 10(-3) M. Under optimal conditions, the biosensor exhibits high sensitivity (0.34 mu A.mM(-1)), low detection limit (1 x 10(-)(4)M), high affinity to glucose (K-m = 0.02 mM), and also good reproducibility (R.S.D. 2.8%, n = 10) and a stability of about ten days when stored dry at +4 degrees C. Besides, the effects of pH value, scan rate, mediator effects on the glucose current, and electroactive interference of the biosensor were also discussed. As a result, the biosensor exhibited an excellent electrocatalytic response to glucose as well as unique stability and reproducibility.