The project is being conducted in collaboration with four Early Head Start programs in the greater Washington, DC area that serve predominantly new immigrant Latino families. Together we are conducting a randomized trial of home-based Early Head Start services with and without a supplemental, attachment-based parenting program, Dozier's "Attachment and Biobehavioral Catch-up" (ABC) intervention. There are three key goals: (1) define criteria for identifying EHS families at risk for experiencing toxic stress and validate these criteria empirically; (2) evaluate through a randomized trial the efficacy and "value added" of supplementing EHS services with the ABC program; (3) evaluate the implementation and sustainability of the ABC program within the EHS context, and the linkages between implementation characteristics and program impacts. The study's findings will advance the knowledge of how EHS can increase support for early parenting and thus buffer infants and toddlers from toxic stress.