An allergy examination was made on forty-eight consecutive bronchiectasis patients, with a mean age of 37 years. Eleven had confirmed asthma and another nine, making twenty in all (42%), had distinct allergic diathesis. Allergy to a specific allergen was established in five cases. 50% of the patients in the total series had bronchial histamine hyper-reactivity, eleven without asthma or distinct allergic diathesis. The results corroborate views previously reported of the role of asthmatic symptoms and allergic diathesis as aetiological factors of bronchiectasis.