We report on a case of T-cell chronic lymphocytic leukaemia involving the lung, with clinical, radiological and histological evidence of relapsing bronchiolitis obliterans-organizing pneumonia in a 70-yr-old female. Pulmonary disease was the major clinical manifestation of this chronic lymphocytic leukaemia. The first two episodes of the patient's pulmonary disorder resolved without treatment, and the third episode was treated with cytotoxic agents as part of the leukaemia treatment regimen. Two additional episodes of the pulmonary disorder occurred; both responded to prednisone.