PROJECT SUMMARY/ABSTRACT Failure to initiate breastfeeding (BF) and exclusively breastfeed (EBF) for the recommended 6-month duration, can result in long-term morbidity among both mothers and their infants. African Americans/Blacks (AA/B) have the lowest BF initiation and EBF rates among all racial ethnicities in the US. AA/B infants have disproportionately high rates of mortality, and children have a high incidence of asthma and sudden infant death syndrome (SIDS) while AA/B mothers are at high risk for chronic illnesses like obesity, diabetes, and cardiovascular diseases. These health disparities cost the US more than $9.1 billion in medical treatment annually but can be reduced by increasing EBF rates. However, AA/B women experience barriers on multiple levels to initiating, continuing BF, and maintaining EBF (either by discontinuing BF or introducing supplements BF with other foods). With high rates of smartphone ownership and consumption of digital content in AA/B women, the proposed mHealth intervention has great potential to increase BF initiation and maintain EBF among AA/B women and has demonstrated feasibility (user satisfaction and use) in our prior completed feasibility study. The proposed SBIR Direct Phase II application, Knowledge and Usage of Lactation using Education and Advice from Support Network (KULEA-NET) addresses an unmet need for an evidence-based mobile app, providing comprehensive BF support and addresses the interrelated and complex BF barriers AA/B mothers experience across the socio-ecological layers. KULEA-NET will provide comprehensive BF support to nurture and support AA/B women in BF initiation and EBF, and include the following innovative features: a) Social marketing and health branding to promote EBF as a socially desirable behavior; b) Micro-learning educational content to improve the acquisition of knowledge and skills related to EBF; c) Support network communication tools leveraging asynchronous communication that allow mothers to communicate with her BF supporters, peers, and lactation professional supports; d) Context-aware delivery framework that will capitalize on user information such as date of delivery, feeding and diaper log data, and location variables to provide timely feedback, content, and guidance; and e) a Virtual community support network bringing together AA/B mothers and their spouse/family members, and fostering a community of mutual support. We hypothesize that KULEA-NET will improve knowledge, BF self-efficacy, and intentions to BF, and ultimately achieve increased BF initiation, BF duration, and EBF rates at 6 months among AA/B mothers and, as a result, improved maternal and infant health outcomes.