PROJECT SUMMARY Depression is one of the most common perinatal complications, with 1 in 7 mothers qualifying for a diagnosis of postpartum depression (PPD) and even higher rates for those who identify as Hispanic/Latine, Black or African American, American Indian, or Alaska Native, or by multiple races or ethnicities. This project addresses this major gap in services to prevent PPD, particularly among socioeconomically disadvantaged and minoritized groups. It tests the benefit of a virtual perinatal preventive intervention in English and Spanish to increase access, scalability and address the mental health needs of underserved populations. This project will test the virtual verison against the in-person version of a service-ready efficacious preventive intervention in a randomized controlled trial (RCT). Consistent with the third priority from RFA-MH-21-240, this effectiveness trial will provide a test of a preventive intervention with a strong evidence base that is scalable and can be delivered with fidelity by service providers in settings where obstetric care is received. In this project, pregnant women will be randomized to receive an evidence-based group prevention program (Reach Out, Stay Strong, Essentials for New Moms; ROSE) designed for perinatal populations either a) in person, delivered at the hospital where they are receiving prenatal care or b) virtually, delivered by the same staff via video conferencing, both offered in English and Spanish. This project will test the following aims: 1: Test effectiveness of a virtual group preventive intervention program on reducing postpartum depression compared to in-person delivery. 2: Identify mechanisms of change for the intervention and characteristics that predict who receives the greatest benefit. 3: Provide implementation recommendations for transporting and sustaining programs in other women’s healthcare settings. The discoveries generated by this project will establish a preventive intervention model that can be implemented at scale in diverse healthcare and community settings as a low-cost, high reach means of preventing postpartum depression.