This thesis discusses how Multi-agent Systems (MAS) should be designed in the context of diabetic health care. Three fields are touched: computer science, socio-psychology and systems science. Agent Technology is the core technology in the research. Theories from socio-psychology and systems science are applied to facilitate the discussion about computer agents. As the integration of socio-psychology and systems science, Activity Systems Theory is introduced to give a synthesized description of MAS. Laws and models are introduced with benefits on both individual agent and agent communities. Cybernetics from systems science and knowledge engineering from computer science are introduced to approach the design and implementation of the individual agent architecture. A computer agent is considered intelligent if it is capable of reactivity, proactivity and social activity. Reactivity and proactivity can be realized through a cybernetic approach. Social activity is much more complex, since it considers MAS coordination. In this thesis, I discuss it from the perspectives of socio-psychology. The hierarchy and motivation thinking from Activity Systems Theory is introduced to the MAS coordination. To behave intelligent, computer agents should work with knowledge. Knowledge is considered as a run-time property of a group of agents (MAS). During the MAS coordination, agents generate new information through exchanging the information they have. A knowledge component is needed in agent’s architecture for the knowledge related tasks. In my research, I adopt CommonKADS methodology for the design and implementation of agent’s knowledge component. The contribution of this research is twofold: first, MAS coordination is described with perspectives from socio-psychology. According to Activity Systems Theory, MAS is hierarchically organized and driven by the motivation. This thesis introduces a motivation-driven mechanism for the MAS coordination. Second, the research project Integrated Mobile Information Systems for health care (IMIS) indicates that the diabetic health care can be improved by introducing agent-based services to the care-providers and care-receivers. IMIS agents are designed with capabilities of information sharing, organization coordination and task delegation. To perform these tasks, the IMIS agents interact with each other based on the coordination mechanism that is discussed above.