AimOral mucositis is a common and debilitating side effect of haematopoietic stem cell transplantation. Our study investigated parents' and children's experiences of oral mucositis treatment and whether the parents' perceptions accurately reflected the children's views. MethodsWe analysed 71 questionnaires completed by the parents of children who had undergone haematopoietic stem cell transplantation, together with 38 questionnaires completed by children who were 7 years of age or over. ResultsThe parent proxy and child self-reports showed good to excellent agreement. For example, 86% of the parents and 83% of the children reported oral pain and 44% of the parents and 47% of the children reported difficulty swallowing often or very often. The majority of the parents (61%) were satisfied with the pain treatment that had been given to their child. However, the treatment provided for oral mucositis was not altogether consistent. ConclusionOral mucositis affected the majority of the children undergoing haematopoietic stem cell transplantation, causing considerable pain and discomfort. The parent proxy reports proved to be reliable and are an important supplement to child self-reports on symptoms related to oral mucositis. But there is a clear need to establish more evidence-based care for children suffering from oral mucositis.