Systems and methods of comparing structured documents are disclosed. From/to source documents are first represented by their respective from/to XML forms based on a predetermined schema. One or more from nodes are selected from the from XML document to compare to one or more to nodes from the to XML document. The comparison employs a set of matching functions that may be selected based on the domain of the source documents. The matching functions may compare just the tags of XML elements, and/or their text contents and/or any of their relevant attributes. The matching may be exact or approximate. Each matching function computes a score which may be weighted. For each pair of from/to nodes, an overall match-score is computed based on the scores of the individual matching functions. If the match-score reaches a matching-threshold, the pair is determined to be a match and further matching is stopped. The techniques are extended for comparing multiple from documents to a to document.