The diagnosis and treatment of a life-threatening disease have adverse consequences on child development and impact the family. This study aimed to investigate bereavement due to the impact of bodily and psychosocial changes resulting from Bone Marrow Transplantation from the perspective of adolescent patients and their parents. This is a qualitative, descriptive, exploratory, cross-sectional study. Nine dyads (patients and mothers / fathers) were included. Data collection took place through semi-structured audio-recorded interviews. The thematic analysis made it possible to elaborate three categories: losses due to illness; new losses experienced with treatment; learning to appreciate the gains of adverse experience. The results show that transplantation has repercussions that transcend the physical dimension and include social harm, changes in body image, and loss of friends. However, once the radical journey of transplantation is over, the participants positively connoted their experience, identifying benefits that go beyond health recovery, such as emotional maturation, improvement of self-esteem, and the ability to socialize.