HRQoL is an important outcome measure for chronic childhood diseases. However, it is infrequently used in Asia due to the difficulty of obtaining appropriately translated and culturally adapted instruments. We adapted the Childhood Asthma Questionnaires C (CAQ-C) previously used in UK and Australia in children aged 11 to 16 years old. OBJECTIVES: To culturally adapt and validate a disease specific HRQoL questionnaire, CAQ-C for childhood asthma in Singapore. METHODS: CAQ-C was adapted after pre-testing in asthmatic children. Changes to the UK and Australia versions were made to reflect the Singapore educational system, culture, language and climate. A cross-sectional validation was conducted. All consenting asthmatic patients aged 11 years and above attending the Specialist Respiratory Clinic in KK Women's and Children's Hospital participated. Patients with other co-morbidities that could significantly affect their HRQoL were excluded. RESULTS: The adapted CAQ-C was validated in 99 patients (41 females and 58 males) with a mean age of 12.84 °Ó1.64 years (range: 10-17 years). More than three quarters completed the questionnaire in 10 minutes or less. The Severity (12 items), Distress (11 items) and Active Quality of Living (4 items) scales had similar internal consistency as the UK and Australian versions (Cronbach's a=0.71-0.85). Our Teenage Quality of Living scale had only 3 items but obtained a Cronbach's a value of 0.62 which is comparable to other versions. The Reactivity scale also had 3 items but its Cronbach's a value was only 0.25. CONCLUSIONS: Childhood Asthma Questionnaire (CAQ-C) is a simple and acceptable HRQoL instrument for asthmatic teenagers. Most found the questionnaire easy and fast to complete. The adapted version has Distress, Severity, Teenage and Active Quality of Living scales with good internal consistency. However, further investigations are needed to determine the internal structure of the scales by factor analysis and improve the Reactivity scale reliability.