The paper defines and clarifies basic concepts of enterprise architectures. Then an overview on architectures for enterprise integration developed since the middle of the 1980s is presented. The main part of the paper focuses on the recent developments on architectures for enterprise interoperability. The main initiatives and existing works are presented. Future trends and some research issues are discussed and conclusions are given at the end of the paper. (C) 2008 Elsevier B.V. All rights reserved.