Theoretical analysis was carried out for the stability of enzymes with pseudo first order kinetics immobilized in three different structures. The stabilities with respect to time and temperature were in the order of core-structured, uniform and shell-structured immobilization methods in contrast to the effectiveness factor order of shell-structured, uniform and core-structured. The shell-structured immobilized enzyme was much more efficient in terms of effectiveness factor than the uniform type, but there was not much difference between time stabilities of the two systems. The core-structured system had the lowest effectiveness factor among the three, but it showed improved stability compared with the two especially when initial Thiele modulus was high.