Bacillus stearothermophilus G-82 cells were immobilized by entrapment in alginate, agarose, agar, carrageenan, polyurethane and polyacrylamide. Polyacrylamide (20%) was the best support for immobilization, providing relatively high pullulanase production with minimal appearance of free cells in the medium. Fifteen-fold elevation of specific enzyme activity in culture liquid was observed for the immobilized system.