Current studies on the storage of XML data are focused on either the efficient mapping of XML data onto an existing RDBMS or the development of a native XML storage. Some native XML storages store each XML node in a parsed object form. Clustering, which means the physical arrangement of objects, can be an important factor in improving the performance in this storage model. In this paper, we propose a clustering method that stores data nodes in an XML document into the native XML storage. The proposed clustering method uses path similarities between data nodes, which can reduce page I/Os required for query processing. In addition, we propose a query processing method using signatures that facilitate the cluster-level access on the stored data to benefit from the proposed clustering method. This method can process a path query by accessing only a small number of clusters and thus need not use all of the clusters, hence enabling the path query to be processed efficiently by skipping unn...