OBJECTIVES Many aspects of QALY measurement in children are not yet fully developed. This study is aimed at contextualizing the mapping methodology in a field not yet covered: paediatric asthma. The objective is to derive utility values from non-preference-based questionnaires, the estimated utility values will be useful for QALY assessment by means of: i) evaluation of a linear mapping between the generic preference-based EQ-5D-3L (self- and proxy-versions) and the condition-specific non-preference-based Paediatric Asthma Quality of Life Questionnaire (PAQLQ) and Paediatric Asthma Caregiver’s Quality of Life Questionnaire (PACQLQ), respectively; ii) assessment of the capability of mapping to discriminate for disease severity.  METHODS Either PAQLQ or PACQLQ and EQ-5D-3L will be administrated to 170 asthma children (7-17 years of age) during a 24-month multicenter randomized placebo-controlled trial of allergen specific sublingual immunotherapy coded EudraCT No. 2012-005678-76/FARM94793N at baseline, month 12, and month 24 visits. Level of severity will be assessed using the Asthma Control Test (ACT) and the Childhood-ACT (C-ACT) questionnaires. The possibility of a linear mapping will be evaluated through a Tobit model, where either PAQLQ/PACQLQ will be tested as predictors of EQ-5D-3L answers. Capability of mapping to be sensible in changes of disease severity will be measured through a Pearson’s correlation between changes in estimated EQ-5D-3L scores and changes in ACT and C-ACT answers. RESULTS Linear mapping, if feasible, applies the statistical relationship between either PAQLQ or PACQLQ and EQ-5D-3L, being PAQLQ/PACQLQ answers predictors of EQ-5D-3L score. EQ-5D-3L and PAQLQ/PACQLQ, as well as EQ-5D-3L built on PAQLQ/PACQLQ answers by applying the linear mapping is expected to discriminate for both patients’ level and changes in disease severity. CONCLUSIONS This study seeks to inform policy makers in their choice of the source of utility values and their discrimination across severity groups and responsiveness in asthma children.