Abstract Production of gallic acid using the immobilized cells of Rhizopus oryzae has been studied. It was observed that 2% tannic acid concentration, 200 numbers of calcium alginate beads of spore concentration 2105/ml and initial pH 5.0 gave the maximum gallic acid production. The % of tannin conversion was 78.5% whereas in free cell culture, the % conversion was 83.5% in 4 days of incubation period. The beads were used for 3 times successfully. A drastic fall in the hydrolysis process was observed when the beads were treated with glutaraldehyde.