Ellagic acid production from cups extract of valonia acorns by pure and mixed cultures of Aspergillus oryzae and Trichoderma reesei was investigated. Ellagitannin acyl hydrolase and xylanase as well as cellulase during the pure and mixed cultures were also determined. The results revealed that mixed culture could produce higher ellagic acid yield (23%) than either of pure culture. And it was found that the three enzymes from mixed culture appeared synergistic effect on ellagic acid production. Statistical analysis showed that ellagic acid yield was correlated very well with the three enzymes activities, resulting in the model for ellagic acid production with high R-2 value of 0.998 and significant level p < 0.004. (c) 2007 Elsevier Ltd. All rights reserved.