PurposeTo explore parents' experience in the decision-making process for children with haematological diseases receiving haematopoietic stem cell transplantation (HSCT) based on genograms. Design and methodsA qualitative study based on genogram was conducted. Seven pairs of parents completed their genogram and a semi-structured interview. Two related donors were interviewed to discuss their experiences in the decision-making process of donating bone marrow to their loved ones. Interviews were transcribed verbatim and analysed using interpretative phenomenological analysis. ResultsThe genogram presents the complete family structure, family member relationships and incident-related conflicts. Two superordinate themes emerged from the data analysis. The first theme was transplantation decision motivations, including four subthemes: the values of life priority, empathy based on kinship, inheritance of family blood, trust in doctors and medical science. The second theme was transplantation decision conflicts, including four subthemes: decision-making conflicts among family members, related-donor decision-making conflicts, risk-benefit game, blind optimism and insufficient cognition conflict. ConclusionsGenogram can show the hidden resources and conflicts of each family and help the care providers better understand parents' experience and the decision-making dilemmas in the decision-making process for children with haematological diseases receiving HSCT. The needs of transplant families for treatment-related information were not fully met. Practice implicationsIt is necessary for medical staff to increase psychological and informational support for donors and their families when the parents of patients make bone marrow transplant decisions. Medical staff should engage in family-focused systematic interventions to reduce the psychological burden and conflicts of decision makers.