Abstract Despite Latinos being the largest ethnic minority, with almost 56.5 million latinos living in the US, they are one of the most medically underserved groups. Latina women have one of the highest rates of gestational diabetes mellitus (GDM) in the U.S. Moreover, GDM is a major risk factor for type 2 diabetes (T2DM), with up to 60% of women developing T2DM within 10 years of a GDM pregnancy. Given the growing obesity epidemic, rates of GDM and T2DM are likely to increase in the absence of preventive interventions. Addressing the risk of T2DM after GDM is critical to reducing health disparities faced by Latina women. The postpartum period is widely-recognized as representing a “window of opportunity” to improve the future health of women who have had complicated pregnancies, including GDM. However, delivery of preventive interventions is challenging due to systems-related factors, including lack of time and resources for providers to provide lifestyle modification counseling, as well as patient challenges, including multiple demands of the postpartum period leaving little time for women to engage in preventive activities. Technology can help overcome these barriers, as demonstrated by the success of our web-based CDC-funded Balance after Baby (BAB) intervention, which successfully promoted weight loss in women with recent GDM. Qualitative results from BAB, which revealed that women strongly wanted the program delivered via an app, led us, in partnership with Latina women with recent GDM, to develop a Phase I m-health intervention program for Latina women, called ¡Hola Bebé, Adiós Diabetes!, in which we tested the preliminary effectiveness of a mobile app in reducing risk factors for the development of T2DM in Latina women who had GDM in the prior 5 years. The proposed Phase II application builds on the promising Phase I results which showed acceptability of the program, increased self-efficacy for healthy lifestyle and weight loss in Latina women with recent GDM. Phase II Specific Aims are as follows: Aim 1: Enhance Hola Bebé to include: a) an IOS version b) integrated databases and data analytics to enable population health management and reporting c) expanded content based on Phase I participant recommendations. Aim 2: Evaluate the effectiveness of Hola Bebé in RCT with Latina women with recent GDM. We hypothesize that participants receiving Hola Bebé will show: increased self-efficacy for healthy eating and physical activity (Primary Outcomes), greater weight loss (Secondary Outcomes), and a greater decrease in HbA1C levels (Exploratory hypothesis) compared to controls. Successful achievement of study aims will result in a culturally tailored, user-centered, low-cost, high- reach, and easy to use evidence-based m-health intervention to reduce risk factors for T2DM in Latina women with a recent history of GDM. The intervention can help reduce the stark ethnic disparities in T2DM among the Latino population while providing a model for an...