Type 1 Diabetes Mellitus (T1DM) portraits a high need and challenge for self-management by young patients: a complex illness with a high and increasing prevalence, a regimen that needs adaptation to patient’s condition and activities, and serious risks for complications and reduced life expectations. When patients do not acquire the knowledge, skills and habits to adhere to their diabetes regimen at childhood, these risks increase suddenly at adolescence. Current mHealth applications have their own specific value for self-management, but are unable to deliver the required comprehensive, prolonged, personalised and context-sensitive support and to reduce these risks persistently. We aim at a Personal Assistant for healthy Lifestyle (PAL) that provides such support, assisting the child, health professional and parent to advance the self-management of children with type 1 diabetes aged 7 - 14, so that an adequate shared patient-caregiver responsibility for child’s diabetes regimen is established before adolescence. The PAL system is composed of a social robot, its (mobile) avatar, and an extendable set of (mobile) health applications (diabetes diary, educational quizzes, sorting games, etc.), which all connect to a common knowledge-base and reasoning mechanism. The robot and avatar act as a child’s pal or companion, whereas health professionals and parents are supported by, respectively, an Authoring & Control and a Monitor & Inform tool. The PAL-project will assess the benefits of the behavioural change on patients’ health conditions, and the profits for the caregivers in longitudinal field experiments. The consortium provides the required network, expertise and tools for this research: (a) a knowledge-driven co-design methodology and tool, (b) medical, human factors and technical expertise, (c) end-user participation and (d) initial PAL building-blocks.