Saccharomyces cerevisiae invertase was immobilized in alginate capsules. The immobilization resulted in 87% relative activity and activity for 36 days without decrease in activity. Optimum conditions for activity were not affected by immobilization and the optimum pH and temperature for free and immobilized enzyme were 4.3 and 60 degreesC, respectively. Immobilized invertase was however, more stable at high pH and temperatures. The kinetic parameters for free and immobilized invertase were also determined. Since the process is simple and invertase does not leak out of capsules, this method can be used for the industrial production of invert sugar.