This study aims to analyze the narratives of children in cancer treatment and their families who are being taken care of, as well as their oncopediatricians who are taking care of. The critical discourse analysis theory gave foundation to this research, from a relationship between
social practice and discursive practice and from the role of some emblematic discourses that penetrates the interaction between subjects. The discourses were further analyzed as for the identity formations, the discursive interfaces of cancer treatment children, their families, and
their oncopediatricians. Linguistic Theory provides the tools to verify the interfaces of discourse of the intra- and inter discourse, modal words, ethos, politeness and metaphoricsemantic elements, which can be a contribution to the education and medical practice process . Health Education must first focus on an open communication between the patients and their families, to know and to respect the language and cultural experiences of the community that
will be assisted, as well as to maintain an ethical attitude inherent to the medical professional