OBJECTIVE:To report the development and psychometric properties of a generic computer-delivered measure of quality of life (QoL) suitable for children aged 6-12 years: the Exqol. The theoretical model adopted is based on an assumption that poorer QoL is the result of discrepancies between an individual's actual ('like me') and ideal self ('how I would like to be'). METHOD:The Exqol consists of 12 pictures, each of which is rated twice; first in terms of 'like me' and second as 'I would like to be'. The Exqol is delivered using a Macintosh Powerbook and takes approximately 20 min to complete. Data are reported for 58 children with asthma (Mage = 8.95 years) and 69 healthy children (Mage = 749 years). In order to determine validity of the Exqol, children with asthma also completed the Childhood Asthma Questionnaire (CAQ) and their mothers completed a measure of child vulnerability and caregiver QoL. RESULTS:Higher discrepancies were found for children with asthma compared with healthy children (P < 0.05). For children with asthma, significant correlations were found between discrepancy scores and two of the four subscales of the CAQ. Children who rated their asthma to be more severe also had higher discrepancy scores (P < 0.05). CONCLUSIONS:The Exqol has acceptable internal reliability and validity and distinguishes between children with asthma and healthy children. These data provide preliminary support for the theoretical assumption that QoL reflects perceived discrepancies between an individual's actual and ideal self. Methodological refinements to the Exqol are suggested.