Abstract There are approximately 43.5 million informal (unpaid) caregivers in the U.S., of which 5.6 million are African American. Informal caregivers often provide a variety of types of support including emotional, physical, and financial, to people with chronic conditions.1 Providing care can be very stressful and emotionally and physically exhausting for informal caregivers.2 African American caregivers have unique needs because they are more likely to experience stressors related to limited support for respite care and a lack of access to culturally sensitive health care providers and services,3-5 placing them at higher risk for burnout and adverse health outcomes.6 Thus, preventing or reducing caregiver stress is especially important in order to sustain informal caregiving. One type of intervention that has shown promise in helping caregivers manage stress, anxiety, and depression is Mindfulness-Based Stress Reduction (MBSR). While MBSR is typically taught in face-to-face group sessions, this Phase I STTR proposes to use MBSR components such as sitting meditations, a body scan, and yoga exercises to create a mobile-friendly application (app) tailored for African American informal caregivers of people with chronic conditions. The proposed app, entitled Mindfulness Based Stress Reduction for African American Caregivers (MBSR-AAC), will employ video and audio adaptations of MBSR activities in addition to content tailored for the target population. Although there are numerous mindfulness apps available, none specifically target African American caregivers, a group of people who could greatly benefit from reductions in anxiety and depression, which, in turn, may improve the mental and physical health of their care recipients. The proposed study will use in-depth qualitative interview data from caregivers and key informants to inform the development of the MBSR-AAC and to evaluate its proposed content, including video and audio presentations. After the MBSR-AAC is developed, a feasibility trial will be conducted to examine usability. Also, ecological momentary assessment-style outcome data will be collected to examine the association between number of minutes using the app and real-time perceived stress. Data from the feasibility trial will be used for final refinements, which will leave the MBSR-AAC well-poised for rigorous efficacy testing in Phase II and rapid market scale-up.