Black patients with serious illness experience higher-intensity care at the end of life. Little research has used critical, race-conscious approaches to examine factors associated with these outcomes. To investigate the lived experiences of Black patients with serious illness and how various factors may be associated with patient-clinician communication and medical decision-making. In this qualitative study, one-on-one, semistructured interviews were conducted with 25 Black patients with serious illness hospitalized at an urban academic medical center in Washington State between January 2021 and February 2023. Patients were asked to discuss experiences with racism, how those experiences affected the way they communicated with clinicians, and how racism impacted medical decision-making. Public Health Critical Race Praxis was used as framework and process. The experience and of racism and its association, as described by Black patients who had serious illness, with patient-clinician communication and medical decision-making within a racialized health care setting. A total of 25 Black patients (mean [SD] age, 62.0 [10.3] years; 20 males [80.0%]) with serious illness were interviewed. Participants had substantial socioeconomic disadvantage, with low levels of wealth (10 patients with 0 assets [40.0%]), income (annual income <$25 000 among 19 of 24 patients with income data [79.2%]), educational attainment (mean [SD] 13.4 [2.7] years of schooling), and health literacy (mean [SD] score in the Rapid Estimate of Adult Literacy in Medicine-Short Form, 5.8 [2.0]). Participants reported high levels of medical mistrust and high frequency of discrimination and microaggressions experienced in health care settings. Participants reported epistemic injustice as the most common manifestation of racism: silencing of their own knowledge and lived experiences about their bodies and illness by health care workers. Participants reported that these experiences made them feel isolated and devalued, especially if they had intersecting, marginalized identities, such as being underinsured or unhoused. These experiences were associated with exacerbation of existing medical mistrust and poor patient-clinician communication. Participants described various mechanisms of self-advocacy and medical decision-making based on prior experiences with mistreatment from health care workers and medical trauma. This study found that Black patients' experiences with racism, specifically epistemic injustice, were associated with their perspectives on medical care and decision-making during serious illness and end of life. These findings suggest that race-conscious, intersectional approaches may be needed to improve patient-clinician communication and support Black patients with serious illness to alleviate the distress and trauma of racism as these patients near the end of life.