Hospice care offers known benefits for terminally ill patients; however, referrals to hospice are often delayed. The objective of this research was to adapt an existing evidence-based intervention (EBI) developed by Casarett et al. to increase hospice care referrals for home- and community-based populations. First, we identified core components of the Casarett EBI by interviewing 5 members of the Casarett research team. We identified two core components of the Casarett intervention: re-framing the hospice conversation to a topic that clinicians felt comfortable discussing and standardizing the conversation in some way. Next, we engaged a stakeholder panel of three home health agencies to identify context differences between the original and new context and necessary adaptations. We identified 14 adaptations to the Casarett intervention, the majority of which were delivery adaptations. We took the 14 adaptations and coded them to develop a theory of how adaptations impact implementation and intervention outcomes. Our theory built on existing implementation science frameworks and showed that although content and delivery adaptations can be made for any reason, the reason for the adaptation drives the its impact on outcomes. Additionally, different types of adaptations have differential effects on implementation and intervention effectiveness. Finally, we pilot tested the adapted intervention to assess its feasibility. We tested the adapted intervention in two home health agencies for 9 weeks, collecting quantitative and qualitative data on outcomes and implementation. Pilot sites implemented intervention activities with high fidelity with relatively low time commitments (5-10 minutes/patient) and minimal re-structuring of clinical workflows. We achieved hospice/palliative care election rates (14%) similar to those found by Casarett (20%). Pilot sites suggested further adaptations to the intervention to improve its effectiveness in this patient population and strategies for scale-up of the intervention. In sum, this research further developed methods for identifying core components, as well as build the foundations for further exploring how adaptations work to influence outcomes through the development of our theory. Through our pilot test, we demonstrated the feasibility of implementing the adapted intervention in practice with minimal support; we offer suggestions for further refining the intervention to increase its usability in practice.