Abstract Background The Yale Cancer Disparities Firewall Project addresses racial/ethnic minority and low socioeconomic status disparities in cancer screening and outcomes by translating evidence-based practices and guidelines into wrap-around support for these populations. Tailoring cancer disparities activities to local needs requires community engagement and participation (CEP). Operationalizing CEP is challenging though its value as a tool to adapt scientific and behavioral knowledge into acceptable patient-level interventions and programs has been recognized. We explored a range of CEP activities implemented within our project to understand and classify the use, outcomes and limitations of community engagement. Methods Comparative qualitative methods highlight variations in how CEP is operationalized. Data from group interviews (n=58; 66% Hispanic and 31% African American) and archival documents were synthesized based on models defined by Popay et al (2006) and Brunton et al (2017). Purposive samples of church-goers, members of a university-convened, community liaison group and a community action network (CAN) established to advise and promote CEP around healthy lifestyles and cancer screening were interviewed. Documents included minutes from a community research engagement subcommittee and supervision meetings for a lay health leader. The research team thematically coded data considering the process, timing, activities, expectations and power dynamics of community engagement. Gaps in community knowledge and access to cancer screening and services were also noted. This poster includes an electronic polling station that collects reader experiences. Results Empirical themes and process maps demonstrate the utility of different types of CEP. Most commonly, community members requested that cancer experts share more information with local populations. CEP generated voluminous suggestions about the outreach process, cancer communications content and channels, and potential barriers to reach and uptake. Additionally, we identified four ways of operationalizing CEP: a) operations advising, b) community knowledge assessment, c) program/intervention planning, and d) document development. Using quotations and visual data, we describe the range of CEP activities, the extent of engagement and institutional capacity required to facilitate each type. A framework for iterative CEP and bidirectional education to advance cancer risk reduction and screening objectives is proposed. Conclusion CEP encompasses diverse activities and can provide practical guidance for project implementation. By examining institutional context and CEP history, researchers may implement CEP more intentionally by presenting scopes of work, degree of engagement and output integration plans to CEP participants. Additional research is needed to demonstrate whether fit-for-purpose use of CEP results in different outcomes. Citation Format: Sakinah C. Suttiratana, Monique Killins, Denise E. Stevens, Jose DeJesus, Roy Herbst, Beth A. Jones. Operationalizing community engagement and participation: Experiences of the Yale Cancer Disparities Firewall Project to impact lifestyle change and cancer screening [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr B045.