One of the trends in the global market is the increasing collaboration among ent- prises. Constant changes in inter- and intra-organizational environments will persist in the future. Organizations have to flexibly and continuously react to (imminent) changes in markets and trading partners. Large companies but also SMEs have to cope with internal changes from both a technical (e.g., new information, communication, software and hardware technologies) and an organizational point of view (e.g., merging, re-organization, virtual organizations, etc.). In this context, the competiti- ness of an enterprise depends not only on its internal performance to produce products and services, but also on its ability to seamlessly interoperate with other enterprises. External and internal collaborative work needs more interoperable solutions. The International Workshop on Enterprise Interoperability, IWEI, aims at identi- ing and discussing challenges and solutions with respect to enterprise interoperability, both at the business and the technical level. The workshop promotes the development of a scientific foundation for specifying, analyzing and validating interoperability solutions; an architectural framework for addressing interoperability problems from different viewpoints and at different levels of abstraction; a maturity model to eva- ate and rank interoperability solutions with respect to distinguished quality criteria; and a working set of practical solutions and tools that can be applied to interoperab- ity problems to date. IWEI is organized by the IFIP Working Group 5.8 on Enterprise Interoperability.