The present report focuses on developing a comprehensive framework that guides the design of ePartners that support behavior change to promote health. An ePartner is an interactive, virtual or embodied computer assistant to which one can communicate and that assists persons through tailored advice, coaching and support. Chapter 2 describes the general framework regarding behavior change. It starts with specifying the desired health goal and the behavior change to reach that goal. Next determinants that affect this behavior (change), and techniques changing these determinants are defined. These steps reflect the first steps of Intervention Mapping (Bartholomew et al., 2011), which is combined with situated Cognitive Engineering (Neerincx & Lindenberg, 2008). In order to evaluate this approach, we used three scenarios to develop baseline requirements for ePartners-that-care. It proved to be an efficient way to develop requirements, given the around 175 requirements and 40 use cases that were developed within the three scenarios in the sCE-tool. The resulting number of requirements, behavior change techniques, determinants, and theories raise the question of managing this vast amount of data. One factor contributing to this large number is the level of abstraction at which requirements and use cases are formulated. Future research should focus on how to make and maintain the amount of theories, determinants, BCTs, and requirements applicable and searchable when designing ePartners-that-care. In addition, content information regarding the specific health (care) problem is also required as input for the ePartner. Chapter 3 addresses how an ePartner can be tailored by describing the various approaches and terminology regarding tailoring. Within the health education domain tailoring is a well-defined approach, incorporating an elaborated ontology that positions tailoring on a dimension from generic, targeted, personalized, tailored to interpersonal communication. Also a method how to design tailored communication is observed in the literature. Finally, Chapter 4 provides a short introduction to the field of persuasive technology, because an ePartner is a technology whose features in itself may encourage its use and impact. The general behavior change framework could be enriched by incorporating elements from tailoring and persuasive technology in its content (behavior determinants and behavior change techniques) and method (situated Cognitive Engineering and Intervention Mapping). However, this also poses the question at which level of abstraction the framework should operate and the scope of the framework.