The objectives of the study were to describe quality of life (QoL), identify predictors of worse QoL and examine QoL during different phases of active therapy for acute lymphoblastic leukemia (ALL). A multiinstitutional cross-sectional study was performed in children with ALL. We included children at least 2 months from diagnosis who were receiving treatment in first remission. Parents described QoL using the PedsQL 4.0 Generic Core Scales and the PedsQL 3.0 Acute Cancer Module. The 206 children on treatment for ALL had overall [median 62.5, 95% confidence interval (CI) 34.8-94.4], physical (median 62.5, 95% CI 18.8-100.0) and psychosocial (median 65.4,2) summary scores that were one to two standard deviations lower than population norms. In high-risk ALL, girls and older children had worse QoL. In standard-risk ALL, those with lower household incomes and unmarried parents had worse QoL. QoL scores were generally constant across phases of ALL therapy. Children on therapy for ALL have lower QoL compared to healthy children. Age and gender predicted QoL in highrisk ALL, whereas socioeconomics predicted QoL in standard-risk ALL. Future efforts should focus on longitudinal studies that describe QoL over time within individual patients.Acute lymphoblastic leukemia (ALL) is the most common cancer in children. Outcomes for children with ALL have continued to improve over time, and currently, almost 80% of children are cured of their disease with primarily outpatient chemotherapy. 1 Because cure rates have increased, more emphasis has been placed on reducing toxicities of therapy, improving quality of life (QoL) during treatment and minimizing long-term effects of therapy. Contemporary chemotherapy regimens for childhood leukemia are lengthy with medications administered over 2.5-3.5 years, and thus, more attention has been directed at understanding QoL during active therapy.To date, published QoL research in pediatric cancer has mainly focused on diverse patient groups, which is appropriate for early exploratory work in describing QoL and validating instruments. However, as our knowledge of QoL in pediatric cancer progresses, it is important to begin to focus on specific subpopulations. Most likely, pediatric cancer patients with differing diagnoses and treatments have different levels and determinants of QoL.Two systematic reviews have examined measurement of QoL for children with ALL. 2,3 Most research has focused on survivorship and much less on the period during active treatment. 2 Of those studies that have included children during active treatment, sample sizes for ALL patients have been small and, in general, have not been designed to identify those more likely to have worse QoL on therapy or to compare QoL during different phases of treatment.Thus, research focused on children with ALL during active treatment is important and remains an area in which we lack knowledge about predictors of QoL and changes in QoL over different phases of therapy. Consequently, our objectives were to describe QoL in a large cohort ...