This volume contains the Proceedings of the Fourth International Conference on Coordination Models and Languages, Coordination 2000. It was held in the wake of three successful earlier conferences whose proceedings were also p- lished in this series, in volumes 1061, 1282 and 1594. The need for increased programmer productivity and rapid development of complex systems provides pragmatic motivation for the development of coordination languages and m- els. The intellectual excitement associated with such endeavors is rooted in the decades-old desire to cope with increasingly higher levels of...