workflow management system supports the automation of business processes where a collection of tasks is organized between participants according to a defined set of rules to accomplish some business goals. the service-orientated computing paradigm is transforming traditional workflow management from a close, centralized control system into a dynamic information exchange and business process. moreover, agent based workflow, from another point of view, provides a flexible mechanism for dynamic workflow coordination at run time. in this context, the combination of web services and software agents provides great flexibility to discover and establish relationships among business partners. this thesis proposes an agent-based workflow model in support of inter-enterprise workflow management. in the proposed model, agent-based technology enables the workflow coordination at both inter- and intra- enterprise levels while semantic web and web services based technologies provide infrastructures for messaging, service description, service discovery, workflow ontology, and workflow enactment. coordination agents and resource agents are used with a contract net protocol based bidding mechanism for constructing a dynamic workflow process among business partners. the agent system architecture, workflow models and related components are described. a prototype system is implemented for the purpose of designing and developing role-feasible agents for simulating the formation process of a virtual enterprise.