Whenever XML data must be shared by heterogeneous applications, transformations between different applicationspecific XML formats are necessary. The state-of-the-art method transforms entire XML documents from one application format into another e.g. by using an XSLT stylesheet, so that each application can work locally on its preferred format. In our approach, we use an XSLT stylesheet in order to transform a given XPath query such that we retrieve and transform only that part of the XML document which is sufficient to answer the given query. Among other things, our approach avoids problems of replication, saves processing time and in distributed scenarios, transportation costs. Categories and Subject Descriptors H2.4 [Database Management]: Systems – Query Processing General Terms Algorithms, Languages Keywords XPath, XSLT, query transformation, query rewriting.