CT of the thorax done during acute severe asthma in two paediatric patients demonstrated central bronchiectasis, a sine qua non for the diagnosis of allergic bronchopulmonary aspergillosis. Bronchography, regarded as the gold standard, was done subsequently on recovery. A comparative segmental analysis revealed that CT was able to identify immediately 24 of 27 segments which showed central bronchiectasis on bronchography. Early diagnosis with the aid of CT enabled immediate intervention which may have helped to prevent further lung damage in the paediatric patients.