This report evaluates quality-of-life (QoL) measures for children and adolescents, focusing on self-report and proxy measures. Four key questions are addressed: (1) How much do adult measures used in children's healthcare interventions? (2) How appropriate are adult measures for children? (3) How do child self-reports compare with parental assessments? (4) How feasible and reliable are proxy measures in different disease contexts? Forty-three QoL measures were identified, including 19 generic and 24 disease-specific. Sixteen measures allowed for child and parent completion, seven only for proxy, and 17 only for child. Measures were categorized as QoL (n=30), health status (n=2), perception of illness (n=1), life satisfaction (n=1), and quality of well-being (n=1). Adult measures were used in three studies with minimal changes for children, and in 11 studies as a model for child work. Adult measures may fail to capture aspects important to children, impose response burden, and require modification for cognitive and language skills. More research is needed to determine the response burden for children of different ages. Child self-reports showed some concordance with parental assessments, particularly in physical functioning, but greater heterogeneity in social and emotional domains. No simple relationship was found between concordance and moderating variables like age, gender, or illness. Proxy measures were evaluated in five studies, but authors often failed to justify their choice or report critical information like completion rates. Existing measures can save time and cost but may be lengthy and demanding for sick patients. They are not recommended for children. Recommendations include developing new measures that consider children's understanding of illness, emotion, and rating scales, and include child and proxy reports. Measures should be developmentally sensitive and include generic and disease-specific modules. Clinical appropriateness requires measures that are suitable for the questions being answered. QoL measures can help evaluate clinical care and are sensitive to changes in children's QoL, especially in those with long-term illness. To improve care, measures should be clearly defined, developed with clinicians, and involve families in their development. QoL is central to paediatric practice, and its measurement is essential for clinical trials and assessing treatment outcomes. The report highlights the need for a holistic approach to QoL, considering both physical and psychological aspects, and the importance of involving children in their healthcare. QoL measures should reflect the child's perspective and be used to inform treatment decisions. The report also emphasizes the need for further research to improve the accuracy and relevance of QoL measures for children.This report evaluates quality-of-life (QoL) measures for children and adolescents, focusing on self-report and proxy measures. Four key questions are addressed: (1) How much do adult measures used in children's healthcare interventions? (2) How appropriate are adult measures for children? (3) How do child self-reports compare with parental assessments? (4) How feasible and reliable are proxy measures in different disease contexts? Forty-three QoL measures were identified, including 19 generic and 24 disease-specific. Sixteen measures allowed for child and parent completion, seven only for proxy, and 17 only for child. Measures were categorized as QoL (n=30), health status (n=2), perception of illness (n=1), life satisfaction (n=1), and quality of well-being (n=1). Adult measures were used in three studies with minimal changes for children, and in 11 studies as a model for child work. Adult measures may fail to capture aspects important to children, impose response burden, and require modification for cognitive and language skills. More research is needed to determine the response burden for children of different ages. Child self-reports showed some concordance with parental assessments, particularly in physical functioning, but greater heterogeneity in social and emotional domains. No simple relationship was found between concordance and moderating variables like age, gender, or illness. Proxy measures were evaluated in five studies, but authors often failed to justify their choice or report critical information like completion rates. Existing measures can save time and cost but may be lengthy and demanding for sick patients. They are not recommended for children. Recommendations include developing new measures that consider children's understanding of illness, emotion, and rating scales, and include child and proxy reports. Measures should be developmentally sensitive and include generic and disease-specific modules. Clinical appropriateness requires measures that are suitable for the questions being answered. QoL measures can help evaluate clinical care and are sensitive to changes in children's QoL, especially in those with long-term illness. To improve care, measures should be clearly defined, developed with clinicians, and involve families in their development. QoL is central to paediatric practice, and its measurement is essential for clinical trials and assessing treatment outcomes. The report highlights the need for a holistic approach to QoL, considering both physical and psychological aspects, and the importance of involving children in their healthcare. QoL measures should reflect the child's perspective and be used to inform treatment decisions. The report also emphasizes the need for further research to improve the accuracy and relevance of QoL measures for children.