Research involving patients with advanced cancer and their families raises ethical issues for researchers. This paper outlines and discusses the ethical considerations associated with conducting a qualitative study, using in-depth interviews, involving patients with advanced cancer who had cachexia and their families. Such ethical issues relate to beneficence, justice, and the research participants' autonomy. Involving patients and their families at this stage of the illness trajectory allows their voice to inform future practice and ensure that delivery of care is client centred. However, the vulnerability of this population must be recognized and incorporated into meticulous planning of studies to ensure ethical research practice is conducted with this population.