Abstract: Tannase production by Aspergillus niger was evaluated under solid-state fermentation and submerged fermentation cultures. The optimum conditions for maximum enzyme production including deferent inoculum ratios, incubation periods, initial pH values, nitrogen and carbon sources were investigated. A. niger was grown as stand cultures in 250 mL conical flasks containing tannic acid powder medium. The maximum production of tannase by A. niger was achieved at inoculum ratio of 2% (v/v), 96 h of incubation period, initial pH 5.0, yeast extract as a nitrogen sources at a concentration of 0.33 g N L-1 and palm kernel powder (PKP) as a carbon source at a concentration of 25% (w/v). PKP was found to be the best carbon source supporting production of 931.27 U L-1 min-1 compared with 6.25 U L-1 min-1 for wheat straw.