HRQoL is an important outcome for chronic childhood diseases such as asthma. However, HRQoL measures are rarely used in young children in Asia due the difficulty of obtaining valid, reliable instruments that are developmental and cultural suitable. We adapt the Childhood Asthma Questionnaires (CAQ) previously used in UK and Australia for use in Singapore. These questionnaires have three versions for different age groups to take into account the developmental changes: CAQ-A (4-7 years), CAQ-B (7-11 years) and CAQ-C (11-16 years). OBJECTIVES: To culturally adapt and validate a disease specific HRQoL questionnaire, CAQ-B for childhood asthma in Singapore. METHODS: CAQ-B was adapted after pre-testing in asthmatic children. Changes to the UK and Australia versions were made to reflect the Singapore school systems, culture, language and climate. A cross-sectional validation was conducted. All asthmatic patients attending the Specialist Respiratory Clinic in KK Women's and Children's Hospital without other co-morbidities that significantly affect their HRQoL were invited to participate. RESULTS: The adapted CAQ-B was validated in 96 patients (40 females and 56 males) with a mean age of 8.7±1.1 years (range: 7-11 years). Most children have no difficulty understanding and completing the questionnaire. The median time to complete a questionnaire was 10 minutes. Internal consistency obtained was slightly lower than UK and Australia (Cronbach's alpha=0.29-0.76). However, this increased to comparable levels (Cronbach's alpha=0.57-0.76) when two items with confusing phrasing and one item on reading enjoyment were removed. The Passive Quality of Living Scale improved from 0.29 to 0.57 when the item regarding reading was eliminated. CONCLUSIONS: Asthma Questionnaire (CAQ-B) is a simple and acceptable HRQoL to children and parents. The adapted version appeared to be reliable and valid. However, further investigation is needed to determine the internal structure of the scales by factor analysis.