Electronic marketplaces can provide several types of business processes depending upon their target audience. A form of such processes is electronic auction. It is a system for accepting bids from bidders and computing a set of trades based on the offers according to a well defined policy. By automating electronic auctions both buyers and sellers can benefit in many ways. In particular they can achieve cost reductions and shorten the duration of the auction processes. The automation of electronic auctions however requires that both buyers’ and sellers’ auction agent have shared understanding of the auction process as well the semantics of the exchanged messages. How this can be achieved is the main topic of this article. In particular, we illustrate what kind of auction ontologies we are using and how they can be maintained in semantic interoperability. In addition we illustrate how ontology managers communicate through SOAP messages. The communication is coordinated by a workflow...