Abstract Introduction: Medical mistrust, characterized by distrust in healthcare providers, institutions, and systems, can hinder effective Patient-Centered Communication (PCC) — a method of healthcare interaction that ensures patients (pts) voices, needs, and values guide clinical decisions and care planning. Medical mistrust can impede effective healthcare delivery, particularly to those from historically marginalized backgrounds. We aimed to explore the effect of race on the association of mistrust with PCC among older Black and White pts with cancer. Methods: Pts were aged 65+, 50% Black, receiving any cancer treatment and were recruited from July 2022 to August 2023. Pts perception of providers’ PCC was assessed using the Patient-Centered Communication in Cancer Care-36 (range: 1-5; higher score=better PCC), and medical mistrust using the Group Based Medical Mistrust Scale (range 12-60; higher score=greater mistrust) which includes subdomains of discrimination, suspicion, and low support. Multivariable linear regression models examined the association of mistrust with PCC separately among Black and White pts controlling for education, income, depression, and anxiety. The interaction of race on the association of mistrust with PCC was also explored. Beta (β) coefficients, 95% Confidence Intervals (CI), and p-values are reported. Results: Forty-three (21 Black) pts, mean age=73.6 years (range 65-86) completed the study. Sociodemographic and psychosocial characteristics was similar, except income <$50,000 was more common among Black than White pts (48% vs 27%; p=0.005) as was unmarried status (57% vs 27%; p=0.020). Between Black and White pts there were no significant differences in the median levels of mistrust (22.5 vs 20.0; p=0.34) and PCC (4.6 vs 4.5; p=0.82). Among Black pts increased overall mistrust and all mistrust subdomains were associated with decreased PCC [Overall Score: (β=-0.06; 95% CI=-0.09 to - 0.02; p=0.003), discrimination (β=-0.20; 95% CI=-0.30 to -0.11, p<0.001); suspicion (β=-0.14; 95%CI=-0.25 to -0.02; p=0.022) and low support (β=-0.15; 95% CI=-0.27 to -0.03; p=0.017)]. Among White pts, only the mistrust domain of low support was negatively associated with PCC (β=-1.21; 95%CI=-0.25 to -0.02; p=0.028). Exploration of racial differences in the association of mistrust and its subdomains and PCC revealed that the association of the discrimination subdomain and PCC varied between Black and White pts at the 9.5% significance level; p=0.095. Conclusion: Black pts with diminished trust in healthcare providers, institutions, and systems, may be less inclined to actively participate in open and collaborative communication with healthcare providers, which could adversely affect their clinical outcomes. Furthermore, considering the trending difference in mistrust domain of discrimination between Black and White pts, developing communication strategies tailored to address discrimination might be key to mitigating mistrust, cultivating strong patient-provider bonds, and advancing health equity among older Black pts with cancer. Citation Format: Nikesha Gilmore, Nikesha Jean, Nikesha Loh, Nikesha Strawderman, Rev Patrina Freeman, Elizabeth Diaz Fontanez, Marquita Thames-Lewis, Lee Kehoe, Marie Flannery, Ronald Epstein, Supriya Mohile, Charles Kamen. Communication barriers: The role of medical mistrust in patient-centered communication in cancer care among Black and White older patients with cancer receiving treatment [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 B029.