OBJECTIVE: To assess how physicians and families understand quality of life (QOL) for NICU patients, and to explore the feasibility of developing a standardized definition for QOL. STUDY DESIGN: Surveys were developed and administered to neonatologists and eligible families. Quantitative analysis was conducted using standard statistical methods. Qualitative analysis was conducted using NVivo software. Focus groups were conducted with the same groups, and audio recordings were obtained and analyzed for recurring themes. RESULTS: Both parents and physicians value QOL as a metric for guiding care in the NICU. Parents were more likely to accept higher levels of disability, while neonatologists were more likely to accept higher levels of dependence on medical equipment. In relation to infant QOL, predominant themes expressed in the parent focus groups were stress levels in the NICU, advocating as parents, and the way in which long-term outcomes were presented by the medical team; in the physician focus group, the ambiguity of predicting outcomes and thus QOL was the main theme. CONCLUSIONS: Both parents and physicians recognize the importance of QOL in the decision-making process for critically ill infants, but the two groups differ in their assessment of what QOL means in this context. These data suggest that QOL cannot be adequately defined for standardized use in a clinical context, and as such, should be used thoughtfully by neonatologists in discussions of end- of-life care.