The application of self-monitoring technologies to the problem of promoting health-related behavioural change has been an active area of research for many years. This paper reports on our investigations into health-related behavioural change within the context of a cardiac rehabilitation programme, and considers the role that selfmonitoring currently plays and may play in the future. We carried out semi-structured interviews with nineteen cardiac rehabilitation participants. Our main findings relate to distinctions between implicit and conscious change, tensions between cardiac rehabilitation and everyday life, the importance of self-awareness and self-determination, and an overall reluctance towards unnecessary selfmonitoring. In view of these findings, we then offer suggestions as to how self-monitoring technologies can be designed to suit this particular context of use. Author Keywords Self-monitoring, cardiac rehabilitation, physical activity, dietary intake, health-related behavi...