Spherical activated carbon was employed as a new support material for the immobilization of urease. Activity and kinetic behavior of the enzyme were observed. Urease activity was decreased by 10% for the uncoated samples during the washing process whereas a 30% reduction in activity was observed for the coated samples due to the electrical discharge. Activity versus time plots generally appeared to be s-shaped curves at different initial urea levels. At high substrate concentration the kinetics no longer obeyed the Michaelis-Menten relationship due to the inhibition mechanism and diffusion for the support system.