Review of the records of 958 patients with multiple myeloma disclosed thoracic skeletal or pleuropulmonary abnormalities or both in 443 patients (46%). The abnormalities were an initial finding on 25% of the chest roentgenograms. The most common finding, exclusive of plasmacytomas, was thoracic skeletal abnormality in 28% (the initial finding in 15%)--osteolytic lesions being the most frequent abnormality. Localized or diffuse pulmonary infiltrates, most often caused by infections, were present in 10%. Four patients had a diffuse infiltrate thought to be caused by a plasma cell infiltrate (proven in one). In 113 patients, plasmacytomas were seen (intramedullary 102, extramedullary 11)--as an initial finding in 8%. Fifty-eight patients (6%) had pleural effusions. Eight patients with pleural effusion caused by myeloma are added to the eight cases reported in the literature.