The biochemical properties of invertase entrapped in alginate gel were studied. The kinetic parameters were determined for immobilized and free invertase. The value of Michaelis constant Km of the immobilized invertase (139.19 mM) was greater than that of the free invertase (93.19 mM), whereas, Vmax was smaller for the immobilized enzyme. Immobilization impressively improved the thermal and storage stability of invertase. The half-life values of the immobilized and free enzymes at 60oC were 28 min and 8 min, respectively. In 0.1 M acetate buffer (pH 4.5) at 2-4oC, the immobilized invertase activity was found to be quite stable after 40 days.