Abstract The goal of this study is to develop best practices for returning results to family child care home (FCCH) directors about pesticides present in their facilities. Best practices will be defined as activities that maximize comprehension of key knowledge and catalyze action to measurably reduce children’s exposure to agricultural and household-use pesticides, thus limiting potentially harmful exposures at an important stage of development. A mixed methods study will be conducted in four Central Valley counties in California in three phases. In Phase 1, multi-stakeholder working groups including local FCCH directors, child care, health and environmental organizations will meet with study staff to discuss ethical issues about reporting back results on pesticides detected in FCCHs using a bioethical environmental justice framework. Qualitative methods will identify common themes to inform the process of reporting back results with the Digital Exposure Report-Back Interface (DERBI) and understanding the barriers and facilitators. In Phase 2, a convenience sample of 30 FCCHs serving ethnically diverse young children in marginalized Central Valley communities will be recruited and participate in a 12-month integrated pest management (IPM) intervention, with carpet dust sampled and assessed for pesticides at baseline and 12 months later. FCCH directors will attend educational workshops, receive environmental assessments, and have regular consultations with study staff focused on IPM goals they have set. Three months post-baseline, FCCH directors will receive access to their pesticide results via the DERBI, including enhancements or modifications resulting from Phase 1 work. Immediately and over the next 9 months, FCCH directors will be interviewed to explore their reactions to and understanding of results, intention to change pest management strategies in response to their report, and plans to share results with families and their community. Throughout Phase 2, researchers will consider the impact of having returned results via DERBI, including barriers to or facilitators of impactful action and unintended consequences of returning results. Upon completion of post-intervention pesticide exposure assessment, Phase 3 of the study will begin. In Phase 3, the FCCH directors and local stakeholders will reconvene along with statewide stakeholders to discuss the quantitative and qualitative results of the IPM intervention, to identify best practices in reporting back pesticide results to FCCH directors, and to write a policy brief. The study aims are: (1) to develop a process for reporting back pesticides detected in FCCHs to program directors by collaborating with key local stakeholders, (2) to determine how an IPM intervention in FCCHs that includes reporting back pesticides using DERBI a) influences directors’ understanding of pesticides, IPM practices, intentions to act on and share their results, and b) whether the intervention subsequently, reduce...