Abstract: While user-centered design is common practice in human computer interaction (HCI), theories of human development have had little influence in HCI design and intervention. In this talk, I will introduce two social cognitive theories that have influenced my conceptualization of what it means to design for children with chronic health conditions. These are the Ecological System’s Theory (EST) and the Health Belief Model (HBM). I will argue these theories of human development and human cognition can inform HCI design and intervention. The EST views a child’s development as being affected by relationships and social contexts; it can be visualized as a set of concentric circles where the child is at the center and is both influenced by and influences the other layers (e.g., family, community, society, environment). The HBM describes the circumstances that encourage individuals to think  in a manner that will lead to improved health. I will discuss how I have used these two models to understand where technology can be targeted and what variables can be manipulated in empirical studies to improve outcomes for children with chronic illness. The EST has led our research team  to a patient-centered approach and to systems that mediate communication between children and their caregivers and among the caregivers; it has also urged us to consider how society can help. The HBM, on the other hand, informs our decisions regarding how to get the child to engage in thought processes that will lead to improved management. I have come to call the combination of these theories an ecological approach to chronic care management. I will also discuss two side effects of using social cognitive theories of human development in system design. First, the resulting systems are inherently generalizable because they are built for “humans” rather than participants.  Second, the ecological approach broadens the definition of a “caregiver” to include people that the individual does not know and may never contact directly.