Introduction: Canada's health systems remain fragmented, an issue further exacerbated by the COVID-19 pandemic. Evidence-informed system transformation towards better integrated care can ensure our health systems and policies are oriented towards achieving the Quadruple Aim and health equity. The Canadian Institutes of Health Research - Institute of Health Services and Policy Research (CIHR-IHSPR) is developing a large-scale research funding initiative Transforming Health with Integrated Care (THINC) to address challenges with implementation, evaluation, and scale of evidence-informed integrated care policies and interventions. This study reports on the process and outcomes of an evidence-informed, community-engaged approach to designing the THINC research funding initiative. Aims and Methods: We aimed to meaningfully engage with patients, providers, researchers, and decision-makers from the health services and policy research community. Participants were identified from the literature, Institute's network, and referrals. We conducted a retrospective analysis of relevant funded research, an environmental scan (2011-2021), and a series of engagements (June - November 2021): semi-structured interviews (n=14), a workshop at the 1st North American Conference on Integrated Care, and three focus groups (n=~8-10 participants per group) among prioritized population groups. Descriptive (quantitative) and thematic (qualitative) analyses were used to identify themes essential for successful integrated care, research investment priorities, and funding design elements. Key Findings: Preliminary findings suggest several elements essential to integrating care, however with a critical need for a better understanding of how to implement and adapt promising interventions and policies for equitable uptake across diverse contexts. Stakeholder engagements identified a common interest in prioritizing research and assessment of impact within integrated care and the need for community-based and community-led solutions. Patients identified the need for patient-led research and strategies for meaningful engagement; providers expressed the need for improving access, data infrastructure and team-based care models for better integration of care; and distinct priorities, needs and challenges were identified among rural and remote communities. There was common agreement across key informants and focus groups about the importance of partnerships among researchers, practitioners, decision-makers and patients/communities. Conclusions: Transformative integrated care remains a priority for patients, providers, researchers, and decision-makers alike to achieve the Quadruple Aim and health equity for all Canadians. Future research investments are needed to support equitable scale and spread of interventions and policies with the greatest potential for transformative impact. Implications for applicability/transferability, sustainability, and limitations: By co-creating and mobilizing knowledge related to the development of this large, pan-Canadian research initiative, we as a federal research funding agency contribute towards learning health systems. Challenges with developing a large strategic research initiative within a short time frame included limited time and resources. [ABSTRACT FROM AUTHOR]