Alkaline protease from Conidiobolus macrosporus was immobilized on polyamide using glutaraldehyde as a bifunctional agent. The immobilized enzyme was optimally active at a higher temperature of 50 degreesC than the free enzyme (40 degreesC ) and showed a ten-fold increased thermostability at 60 degreesC compared to that of the free enzyme. The efficiency of immobilization was 58% under the optimal conditions of pH and temperature. There was a 14-fold decrease in the K-m of immobilized enzyme compared to the free enzyme. The immobilized enzyme was fully active even after twenty-two cycles of repeated use. It retained 80% activity at 50 degreesC in presence of 8 M urea exhibiting its stability to the denaturant and was compatible with several commercial detergents.