In nursing care, existential concerns have been recognized since Nightingale and existential health has been highlighted recently with the Swedish government ordering a report to further national efforts on the subject. There is no consensus in the literature regarding the meaning of existential health, not even in the oncological context where existential concerns are common. Current theoretical perspectives together with person-centred care may guide oncological nursing towards an understanding of existential health that will benefit patients. The literature describes existential health in many ways; opposite existential suffering, a reflexive concept of health, well-being related to spiritual practices or beliefs, the ability to experience health despite hardships and as an aspect of health along physical, mental and social. The arguments of how to conceptualize existential health are primarily made from psychology of religion and existential psychotherapy. Psychology of religion emphasizes meaning and being a part of something greater, while existential psychotherapy emphasizes the adverse aspects of human existence. However, some consensual features are that existential health is deeply personal, relating to meaning, attitudes towards death and belonging. We propose to understand existential health as a process consisting of the reflexive capacity to feel healthy despite illness and adversity, and the fundamental concerns of human existence; meaning, relationships, freedom, bodily agency, awareness of life and death.  In a partnership the person's existential health can be understood through the narrative in hope of cure or in fear of suffering. By approaching the reflexive through the existential concerns in the narrative, caregivers may together with the person identify what in their experience that affects their existential health. A dynamic understanding of existential health will aid health care professionals in supporting patient’s overall health despite the many hardships brought by cancer. Further, it may promote a holistic approach to oncological care through person-centredness.