Objective: The aims of this study were to assess the level of agreement and the magnitude of discrepancies between children and their parents, and whether these levels of agreement/discrepancy depend on the country of living, the domains of quality of life assessed, the age and gender of the children, and other background variables. Study Design and Setting: The KIDSCREEN pilot study involved 2,526 youth-proxy pairs in seven European countries. The health-related quality of life (HRQoL) of children and their parents as proxy has been assessed in parallel using a 10-dimension KIDSCREEN-52 Pilot test questionnaire. Results: For the 10 dimensions, the mean difference between proxy and youth score decreases as the HRQoL level increases. Physical and cognitive domains showed the major agreement between youth and proxy measure. Social and psychological domains presented the main discrepancies. Linear regression models highlighted that the agreement was depending on the country for the 10 dimensions. Impact of age and gender on agreement were not consistent across the 10 dimensions. Conclusion: Agreement is higher for the girls than for the boys and for the adolescents than for children. To further explore the country effect on agreement, results need replication in representative studies. © 2007 Elsevier Inc. All rights reserved.