Background Childhood cancers affect about 350 children every year in Sweden and are life-threatening diseases. During the treatment period, situations arise that can become morally challenging for the child. When knowing children’s values and morally challenging situations in childhood cancer care, targeted ethics support could be developed and used in care. Aim To explore children’s values and moral dilemmas ​​when undergoing cancer treatment. Methods This is a qualitative study based on empirical data. The data collection was conducted through three focus (...) group interviews and six individual interviews with children between 10 and 18 years (n = 16). A content analysis methodology was used to generate themes. Children who were/have been treated for cancer at three childhood cancer centres in Sweden were invited to participate. The study was approved by the Swedish Ethical Review Authority. The children’s participation was based on voluntariness and consent/assent. Findings During the analysis, five themes of values emerged: Personal relationships, Bodily ease and identity, Feeling in control and being involved, Positive distractions and Right care that is needed. Their moral dilemmas were thematized into: Should I consider others or not? Should I rest or not? and Should I refuse treatment or not? Conclusion Children undergoing cancer treatment want to have personal relationships with healthcare professionals. Their moral dilemmas were about questioning their own physical and psychological well-being against their expectations, the values of others and the treatment required. Further research is needed to understand how to deal with moral dilemmas in children undergoing cancer treatment. (shrink)