Abstract Background: In America, Black metastatic breast cancer (MBC) patients are disproportionately underrepresented in clinical research, of which the majority of participants are white - leaving research less representative of Black patients. Interventions: To increase the sustainable participation of Black MBC patients in clinical research, Count Me In (CMI)—a cancer research initiative based at the Broad Institute of MIT and Harvard—partnered with the Tigerlily Foundation (TLF), a patient advocacy organization, to develop an equitable, collaborative approach connecting CMI researchers with Black MBC patients to create culturally relevant educational materials for the Black MBC community. Findings: Participating Black MBC patients developed the following materials: a tri-fold brochure, two types of informational postcards, and a social media digital toolbox. The patients co-developed and approved the materials' content and design elements. Materials were also translated into Spanish. Three iterations were drafted until materials were submitted to CMI’s IRB at Dana-Farber Cancer Institute (DFCI) for approval. The distribution strategy for materials to the larger Black MBC community was designed collaboratively with patients. This included sharing information and resources with their local oncology nurse navigators, placing printed materials in community practices, enclosing materials in folders distributed at initial diagnosis, and further connecting with other community-based breast cancer support groups and organizations. During the pilot distribution period - from August 2023 to February 2024 - CMI sent informational packages with materials to 8 different community contacts across the United States. Participating patients had shared contact information of those in their own social network. By the end of the pilot period, 38 new patients registered in CMI identified as having MBC, with 18% self-identifying as Black/African American and 24% self-identifying as Hispanic/Latino - both of which are overrepresentative when compared to the general population of those who self-identify as Black/African American and Hispanic/Latino. Conclusion: CMI and TLF utilized an equitable approach that included patients at the initial planning of a project to the final production and distribution of the materials. Two recommendations could be provided to researchers and organizations from this successful collaborative partnership and pilot. First, patient advocates desire to be involved in creating and sharing resources with their communities. Organizations can honor their commitment with financial and non-financial opportunities. Second, partnering appropriately with patient advocates will increase clinical study representation. The success of this pilot demonstrates how researchers and patients can collectively close the inequities gap and pave the path forward for more equitable cancer research. Citation Format: Colleen M. Nguyen, Eboney D. Thompson, Juanita Miller, Shanette Caywood, Tiana Russell, Sue Steele, Virginia Leach, Lizzie Wittig, Taisha Hendrickson, Kolbe Phelps, Priyanka Bhakhri. Reaching the Community: Collaborating with Black/African American Metastatic Breast Cancer Patients and Advocates [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr B004.