Abstract. In this paper we propose a new approach to XML benchmarking – a flexible XML query benchmark called FlexBench. The flexibility is given by two aspects. Firstly, FlexBench involves a large set of testing data characteristics so that a user can precisely describe the application. And, secondly, FlexBench is able to adapt the set of testing query templates to the particular set of synthesized testing data. Hence, contrary to the existing works, the testing is not limited by the fixed set of queries and basic data characteristics (usually only size) to a single (and often simple) application. We depict the advantages of the proposed system using a set of preliminary experiments.