Real-world information containing subjective opinions and judgments has emerged the need to represent complex and imprecise data in databases. Additionally, the challenge of transferring information between databases whose data storage methods are not compatible has been an important research topic. Extensible Markup Language (XML) has the potential to meet these challenges since it has the ability to represent complex and imprecise data. In this thesis, an XML based fuzzy data representation and querying system is designed and implemented. The resulting system enables fuzzy querying on XML documents by using XQuery, a language used for querying XML documents. In the system, complex and imprecise data are represented using XML combined with the fuzzy representation. In addition to fuzzy querying, the system enables restructuring of XML Schemas by merging of elements of the XML documents. By using this feature of the system, one can generate a new XML Schema and new XML documents from the existing documents according to this new XML Schema. XML data used in the system are retrieved from Internet by Web Services, which can make use of XML&rsquo / s capabilities to transfer data and, XML documents are stored in a native XML database management system.