Abstract. The paper presents an approach towards executing transactions between enterprises, governmental bodies and banking institutions, based on ERP applications connected over the Internet. The work builds on a review of current XML standards for representing business processes and data (e.g. ebXML, UN/EDIFACT, RosettaNet, ebisXML) as well as standards for the technological deployment of such solutions (CORBA, .net, J2EE). Next, using proven enterprise modeling methodologies, key inter-enterprise transactional processes are being described (e.g. invoicing, banking transactions, VAT or Tax declaration). For the automation of those processes, application-neutral protocols, electronic data formats, and messages for interoperating applications are defined, in XML-based schemas. Finally, a server-based system for managing electronic transactions, such as e-invoicing, e-VAT, and e-payment is designed and deployed among the various transacting organisations.