The provision of medical care typically involves a number of individuals, located in a number of different institutions, whose decisions and actions need to be coordinated if the care is to be effective and efficient. To facilitate this decision making and to ensure the coordination process runs smoothly, the use of software support is becoming increasingly widespread. To this end, this paper describes an agent-based system which was developed to help manage the care process in real world settings. The agents themselves are implemented using a layered architecture, called AADCare, which combines a number of AI and agent techniques: a symbolic decision procedure for decision making with incomplete and conflicting information, a concept of accountability for task allocation, the notions of commitments and conventions for managing coherent cooperation, and a set of communication primitives for interagent interaction. The utility of this approach is demonstrated through the development of an application prototype for the clinical process of cancer treatment.