ABSTRATC Study based on Heidegger's existential phenomenology. The objective was to understand the experience of parents of children with cancer in treatment failure conditions. Participants were eight parents of eight patients seen at an oncology center from January to May 2014. Interviews were conducted guided by the question: Tell me about your experience of being a family member of a child with cancer in treatment failure conditions? Three ontological themes emerged: the phenomenon unveiled in the discovery of the child's cancer; experiencing the process involving the child's cancer; unveiling the possibility of the child's death. It was evidenced that the experience of these parents was permeated by intense and devastating feelings towards the early loss, annihilating dreams of a desired future. It is essential for nursing to look more attentively at the family of terminal patients.