AimsImplementing maternal depression screening in child-serving programs can help ensure that more mothers receive mental health services. This study examined the implementation of universal maternal depression screening in community-based Head Start programs. MethodsQuantitative and qualitative data were merged in a convergent mixed method design to assess four domains from the RE-AIM implementation science framework (Reach, Adoption, Implementation, and Maintenance). Qualitative data included interviews with stakeholders and meeting minutes from the implementation period. Quantitative data included intervention outcomes and administrative data. ResultsIn terms of reach, 85% of eligible Head Start mothers were screened for depression, and English-speaking mothers were more likely to refuse screening than Spanish-speaking or bilingual mothers. Barriers to screening included lack of availability, stigma, privacy concerns, lack of interest, and lack of trust. In terms of adoption, all sites and staff adopted screening due to organizational mandates. In terms of implementation, there was wide variation in rates of positive screenings across staff completing the screening (ranging from 0% to 46%), and barriers included concerns about staff role and lack of training. In terms of maintenance, screening was not sustained after the study period due to organizational priorities and lack of buy-in from staff. ConclusionUniversal maternal depression screening has the potential to reach low-income Head Start mothers, but additional efforts should be made to build staff capacity to engage mothers in screening.