Palliative care may be an opportunity to discuss cancer family history and familial cancer risks with patients' relatives. It may also represent the last opportunity to collect, from dying patients, clinical data and biospecimens that will inform cancer risk assessment and prevention in their surviving relatives. This study aims to explore the perspectives of cancer patients' relatives about cancer heritability, addressing cancer family history, and performing genetic testing in palliative care settings. Thirteen first-degree relatives of cancer patients who died in palliative care participated in the study. Two focus groups were conducted and transcribed verbatim. Two independent coders conducted a thematic content analysis. The themes included: (1) Knowledge of cancer heritability; (2) Experiences and expectations regarding cancer family history discussions, and (3) Views on genetic testing in palliative care patients and DNA biobanking. Participants seemed aware that cancer family history is a potential risk factor for developing the disease. They considered the palliative care period an inappropriate moment to discuss cancer heritability. They also did not consider palliative care providers as appropriate resources to consult for such matters as they are not specialized in this field. Participants welcomed DNA biobanking and genetic testing conducted at the palliative care patients' request. Cancer occurrence within families raises concerns among relatives about cancer heritability, but the palliative care period is not considered the most appropriate moment to address this issue. However, discussions about the risk to cancer patients' relatives might need to be considered on a case-by-case basis.