Metastases develop in 50-60% of patients with high grade soft tissue sarcomas despite primary treatment. Between 1970 and 1990, 189 patients with soft tissue sarcoma referred to the Royal Marsden Hospital Sarcoma Unit developed lung metastases as the sole first site of disseminated disease. 44 of these 189 cases have been treated by pulmonary metastasectomy. In an attempt to determine which patients benefit from this surgery the medical records, radiology and pathology of these cases have been reviewed. Both the overall 5 year survival (70% vs 19%) and the subsequent survival from the time lung metastases developed (52% vs 7.5%) of those selected for thoracotomy were better than in the 145 patients not undergoing surgery. On multivariate analysis, survival and control of lung disease following resection were not related to the number of metastases resected, completeness of excision, use of adjuvant chemotherapy or presence of bilateral disease. The most important factor was the use of lung resection itself as treatment, for which the risk of death was 0.2 compared with those not having metastasectomy. Age less than 40 years and primary tumour in a lower limb site were also factors associated with a reduced risk of death. Pulmonary metastasectomy should be considered in selected patients with soft tissue sarcoma after primary local cure. However, without collection of prospective data on all patients developing lung metastases or a randomized trial the true role of lung metatasectomy will never be clarified.