Tannase has many important applications in animal feed, chemical, food, and pharmaceutical industries. In the present study, optimization of tannase production by Streptomyces sp. AT13 was carried out using statistical experimental designs. Initially, a Plackett-Burmen design (PBD) was employed to screen the preferable nutriments (carbon and nitrogen sources of the medium) to produce tannase. The result showed that only tannic acid was found to be signifi cant for the production of tannase by Streptomyces sp. AT 13. The signifi cant factor was further optimized by using Box-Behnken design under response surface methodology (RSM). From among 6 fermentative variables that were studied, 5 signifi cant variables were picked up by PBD. Among 5 variables from PBD, 3 were further optimized by Box-Behnken design. The parameters studied through RSM were 1% Tannic Acid, 0.5 % KCl and 0.1 % KH 2 PO 4. Under optimized conditions tannase activity was 18.12 U/ml/min. This activity was almost three times higher as compared to the amount obtained by 'one-at-a-time' approach. (5.19 U/ml/min) 691 Biotechnological Communication