One hundred and four patients are reviewed who were found to have thoracic metastases arising from distant primaries. Ninety lesions were intrapulmonary and the remainder involved other thoracic structures, such as chest wall and pleura. The tissue diagnosis was established in all but eight patients. Cases were included only if review of the histology revealed that both primary and secondary tumours were identical. The chest lesion was the presenting feature of the disease in 21 patients. In the remainder, the interval between treatment of the primary and appearance of the thoracic metastasis varied from a few months to 25 years. Twelve patients had metastatic sarcoma. The remainder had metastases from the gastrointestinal tract (29), from the genitourinary tract (32), from breast primaries (18), and a miscellaneous group (13) which included five instances of malignant melanoma and metastases from adrenal, laryngeal, and thyroid primaries. The metastases were treated surgically in 47 patients. In the light of cell type, availability of nonsurgical methods of treatment, site of metastasis, and survival, an attempt is made to evaluate the place of surgery in the management of thoracic metastatic disease.