The clinical and radiological features of seven cases of bronchiolitis obliterans organizing pneumonia (BOOP) are presented and the literature is reviewed. Six of these cases were idiopathic, one patient had rheumatoid arthritis. Detailed respiratory function tests were available in four cases and showed a restrictive defect with impaired gas transfer. The majority of chest radiographs showed consolidation with no zonal preponderance. One case with unilobar consolidation was mistaken for malignancy. Another case with interstitial shadowing was thought to have cryptogenic fibrosing alveolitis. In those cases with consolidation, it was mainly peripheral. Six of the cases showed good response to oral steroid therapy. Open lung biopsy was the principal means by which tissue was obtained for diagnosis. BOOP should be included in the differential diagnosis of multifocal consolidation. The condition is usually responsive to steroid therapy, so it is important to confirm the diagnosis histologically.