OBJECTIVES: To examine distribution, content and construct validity of the EuroQuol-5D-Youth (EQ-5D-Y) in a European sample of asthmatic children. METHODS: A subsample of 69 children with asthma (6-11 years) included in the ASTROLAB cohort completed the EQ-5D-Y online questionnaire. The EQ-5D-Y is a brief, multi-attribute, generic, preference-based health status measure consisting of five dimensions with three response levels. Index values were calculated using the EQ-5D-3L preference value sets for France. The distribution of the index was assess in terms of central tendency, dispersion, proportion of children with perfect health, and observed range. Construct validity was tested comparing known groups defined by the Royal College of Physicians 3 Questions (RCP3Q) for children, that measures asthma control: RCP3Q> 1 not well-controlled and RCP3Q 0-1 well-controlled. The magnitude of the difference was measured by effect size coefficient (ES=difference in mean scores/pooled standard deviation). RESULTS: Mean EQ-5D-Y index was 0.878 (0.211). The observed range was -0.12 to 1. Floor and ceiling effects were 0% and 50%, respectively. It is noteworthy that >20% of children reported problems in Everyday activities, Pain/discomfort and Happiness/worry/sadness. Mean EQ-5D-Y index for children with well-controlled asthma was 0.94 (95% CI 0.91 to 0.96); and 0.82 (95% CI 0.72 to 0.91) for patients not well-controlled (p=0.015). The ES between both groups was moderate (ES: 0.6). CONCLUSIONS: The new EQ-5D-Y presented adequate pattern of distribution among domains despite the index ceiling effect was considerable. The relevant difference between known asthma control groups indicates good construct validity for assessing health related quality of life in these children.