Research in the domain of multi-agent systems (MAS) is becoming more and more important because of the capacity of MAS to design and simulate complex systems, i.e. systems composed of many entities in non-linear interaction between themselves and with an external environment. MAS are used in many domains in which classical mathematical models are not available because either the dynamics are far from equilibrium, or the systems are open (creation and deletion of entities in the course of simulation), or emergent phenomena have to be explored, or the entities are heterogeneous (for example, the eco-socio-systems which combine ecological and social dynamics), or simply because they provide a more intuitive understanding. This workshop is intended to offer a forum for people interested in agentbased simulation to discuss methodologies, techniques and applications. [...] This issue shows the vitality of the multi-agent system modelling simulation community by the diversity of domain in which MAS is applied: - Water management, - Traffic, - Cognitive science, - Sociology, - Economy and a lot more in a number of paper grouped in the application tracks. Of course all this activities need careful understanding of the concepts and implementations underlying this approach, which are presented in its own track. Finally, the invited speakers will present a state of art on multi-agent modelling and simulation of both eco- and socio- systems as examples of very complex systems.