The radiographs of 100 patients with allergic bronchopulmonary aspergillosis were examined to assess the type and distribution of abnormalities seen during long-term follow-up. Lobar shrinkage occurred almost exclusively in the upper zones but other abnormalities were distributed throughout both lungs. Bronchial wall thickening was the commonest lesion observed and was usually a permanent finding. Consolidation was commonest in the perihilar regions, persisted for up to 20 weeks when transient and was a permanent finding in 10 patients. Dilated bronchi were noted to change in calibre with exacerbations and remissions of the condition. Episodes of transient collapse were segmental, lobar or involved a whole lung. Permanent collapse was always segmental. Massive shadowing, band shadows and 'gloved fingers' were seen less frequently than expected and cavitation was rare. In some patients the chest radiograph was normal between exacerbations of the disease.