This paper deals with negotiation between partners (organizations) in the context of loose Inter- Organizational Workflow (IOW). By negotiation between partners, we mean all the conversation acts made between a requester partner looking for a workflow service and one or several selected provider partner(s) able to provide the requested service.

The agent technology is at the basis of our proposition since (i) it provides natural abstractions to deal with distribution, heterogeneity and autonomy which are inherent to loose IOW, (ii) it introduces powerful concepts such as groups and roles useful to describe in details the coordination of the different partners involved in the negotiation, and (iii) it has investigated the problem of negotiation between agents.

In this paper, we first answer the following question "What kind of negotiation is suitable in loose IOW?" identifying what kind of agent behavior (competitive or cooperative) and what kind of negotiation protocol (auction, heuristic, argumentation or Contract-net) better suit loose IOW. We also propose an agent-based architecture, compliant with the Workflow Management Coalition reference architecture, to support negotiation between partners, and an organizational model based on the AGR (Agent- Group-Role) meta model, which structures the negotiation in terms of Agents, Groups and Roles.