Project Summary With over 6 billion mobile phone subscribers and 75% of the world having access to a device, global health communities increasingly recognize the potential for using these devices to improve access to health care and health outcomes?especially in sub-Saharan Africa (SSA), where device ownership has grown dramatically. Less attention, however, has been given to developing the research capacity to allow these countries' public health researchers to collaborate with software developers and the users of mHealth applications (henceforth apps) to develop their own interventions. If mHealth apps are to be adopted, effective, and scalable, they must be designed by and with these individuals, the people most knowledgeable about the issues affecting technology use and disease management in their countries. Human-centered design (HCD), or design thinking, is a promising design strategy that prioritizes the needs of the intended population. It has also been successfully used to develop innovative and locally relevant health interventions that improve health outcomes. The purpose of this R21 proposal is to introduce Kenyan public health researchers and software developers to the HCD process and then collaboratively develop and evaluate an mHealth app that targets a growing epidemic among middle-to-late adolescents (13-18 yrs.) in Kenya?Type 1 Diabetes (T1D). To achieve this goal, we will pursue these specific aims: (1) train Kenyan health practitioners and software developers in HCD; (2) use HCD to build a prototype mHealth intervention for adolescents in Kenya with T1D; and (3) assess the prototype's usability, accessibility, and feasibility in using it to increase adolescents' knowledge of T1D and management of the disease. Our long-term goals include: (1) building research capacity by establishing a research network between health researchers at The Kenyan Diabetes Management and Information Center (DMI?a non-profit organization that works with adolescents with T1D) and mobile software developers at LakeHub (an innovation space in Kisumu) so they can design future mHealth apps; (2) developing a commercially available app that Kenyan adolescents can use to manage T1D and stay healthy; and (3) evaluating the HCD process as it applies to developing mHealth interventions that improve health outcomes.