This study examined the factors that parents identified as influencing their role in treatment decision making (TDM) for their child with cancer. Content analysis of qualitative data from semistructured interviews with 36 parents as part of a mixed-methods study revealed numerous themes related to parents' TDM roles. Factors that were frequently identified included: relationship with the physician, nature of communication, trust in the physician, parents' and physician's knowledge and experience, and importance of parental role. Parents acknowledged a strong sense of responsibility and feeling of "ownership" of their child. Parents initially lacked knowledge and experience, but acquiring these over time contributed to a more active participation in TDM.