Introduction: Vulnerability is a poorly understood concept in research ethics, often aligned to autonomy and consent. A recent addition to the literature represents a taxonomy of vulnerability developed by Kipnis, but this refers to the conduct of clinical trials rather than qualitative research, which may raise different issues. Aim: To examine issues of vulnerability in cancer and palliative care research obtained through qualitative interviews. Method: Secondary analysis of qualitative data from 26 black Caribbean and 19 white British patients with advanced (...) cancer. Results: Four domains of vulnerability derived from Kipnis’s taxonomy were identified and included: (i) communicative vulnerability, represented by participants impaired in their ability to communicate because of distressing symptoms; (ii) institutional vulnerability, which referred to participants who existed under the authority of others—for example, in hospital; (iii) deferential vulnerability, which included participants who were subject to the informal authority or the independent interests of others; (iv) medical vulnerability, which referred to participants with distressing medical conditions; and (v) social vulnerability, which included participants considered to belong to an undervalued social group. Participants from both ethnic groups populated all these domains, but those who were black Caribbean were more present among the socially vulnerable. Conclusions: Current classifications of vulnerability require reinterpretation when applied to qualitative research at the end of life. We recommend that researchers and research ethics committees reconceptualise vulnerability using the domains identified in this study and consider the research context and interviewers’ skills. (shrink)