BACKGROUND: This study investigated the agreement between self-reports from pediatric brain tumor patients and proxy reports from their parents regarding the patients' quality of life (QOL), as assessed using a brain tumor-specific QOL assessment tool, the Pediatric Functional Assessment of Cancer Therapy-Childhood Brain Tumor Survivors (pedsFACT-BrS) questionnaire. The authors expected moderate correlation and similar mean scores between patient and parent reports. METHODS: The pedsFACT-BrS for those aged 7 to 18 years was completed by 351 brain tumor patients (166 children and 185 adolescents), and the parent proxy reports were completed by 351 mother proxies and 37 father proxies. Statistical analyses, including the Pearson product-moment correlation coefficient, intraclass correlation, and comparison of group means, were used to compare the 33 items shared by all 4 versions of the peds-FACT-BrS. RESULTS: The correlation between reports completed by pediatric patients and their parent proxies was significant (P ¼.59-.84), whereas that between the reports of adolescent patients and their parent proxies was slightly weaker (P ¼.47-.78). The patient and parent proxy reports showed moderate-to-good agreement and yielded similar mean scores in both the child and adolescent brain tumor patient groups; the sole exception was a difference in emotional well-being scores. CONCLUSIONS: The results indicate that proper use of the pedsFACT-BrS for patients and their parent proxies can provide clinicians with valid information about the overall QOL of child and adolescent brain tumor patients, including both their general health and their brain tumor-specific well-being. Cancer 2010;116;3674-82.