This article presents the models of an agent-oriented methodology called MAS-CommonKADS . This method- ology extends the knowledge engineering methodology CommonKADS with techniques from object-oriented and protocol engineering methodologies. The methodology consists of the development of seven models: Agent model that describes the agents; Coordination model that describes the interactions between soft- ware agents; Communication model that describes the interactions between human and software agents; Expertise model that describes the reasoning process of the agents; Task model that describes the tasks that the agents carry out; Organisation model that describes the social structures between human and software agents; and Design Model that describes the design decisions about the agent architecture and agent network. The main advantages of the application of this methodology are: (1) a clear software devel- opment life cycle for multiagent development; (2) graphical and textual notation for each model; (3) project management through the de nition of landmark states in each model; (4) usage of standardised languages for describing the conversations between the agents; and (5) usage of knowledge engineering techniques for knowledge acquisition and knowledge reutilisation.