Abstract. We propose a mediator model for providing integrated and unified access to multiple taxonomy-based sources. Each source comprises a taxonomy and a database that indexes objectsunderthetermsofthetaxonomy.Amediatorcomprises a taxonomy and a set of relations between the mediator's and thesources'terms,calledarticulations.Bycombiningdifferent modes of query evaluation at the sources and the mediator and different types of query translation, a flexible, efficient scheme of mediator operation is obtained that can accommodate various application needs and levels of answer quality. We adopt a simple conceptual modeling approach (taxonomies and intertaxonomy mappings) and we illustrate its advantages in terms of ease of use, uniformity, scalability, and efficiency. These characteristics make this proposal appropriate for a large-scale network of sources and mediators.