INTRODUCTION:In the USA, African American men bear a disproportionate burden of prostate cancer (PCa) compared with all other groups, having a higher incidence and mortality, poorer quality of life and higher dissatisfaction with care. They are also less likely to receive guideline-concordant treatment (eg, undertreatment of aggressive disease). Inadequate patient-provider communication contributes to suboptimal care, which can be exacerbated by patients' limited health literacy, providers' lack of communication skills and time constraints in low-resource, safety net settings. This study is designed to examine the communication experiences of African American patients with PCa as they undertake treatment decision-making. METHODS AND ANALYSIS:Using an ethnographic approach, we will follow 25 African American men newly diagnosed with PCa at two public hospitals, from diagnosis through treatment decision. Data sources include: (1) audio-recorded clinic observations during urology, radiation oncology, medical oncology and primary care visits, (2) field notes from clinic observations, (3) patient surveys after clinic visits, (4) two in-depth patient interviews, (5) a provider survey, and (6) in-depth interviews with providers. We will explore patients' understanding of their diagnoses and treatment options, sources of support in decision-making, patient-provider communication and treatment decision-making processes. Audio-recorded observations and interviews will be transcribed verbatim. An iterative process of coding and team discussions will be used to thematically analyse patients' experiences and providers' perspectives, and to refine codes and identify key themes. Descriptive statistics will summarise survey data. ETHICS AND DISSEMINATION:To our knowledge, this is the first study to examine in-depth patient-provider communication among African American patients with PCa. For a population as marginalised as African American men, an ethnographic approach allows for explication of complex sociocultural and contextual influences on healthcare processes and outcomes. Study findings will inform the development of interventions and initiatives that promote patient-centred communication, shared decision-making and guideline-concordant care. This study was approved by the University of California San Francisco and the Alameda Health System Institutional Review Boards.