With the aim of assessing the role of surgery in the management of isolated mediastinal lymphoma, we have reviewed the data of 123 operations performed on 102 patients (64 with Hodgkin's disease and 38 with non-Hodgkin's lymphoma). One death and four major complications occurred in these patients. Macroscopically radical resection was performed in 14 patients who are free of disease after 1 to 14 years. Debulking resection was performed in five patients: Three are alive after 5 to 11 years and two died after 36 and 40 months. Ten patients (seven with non-Hodgkin's lymphoma and three with Hodgkin's disease) had residual mediastinal masses of more than 2 cm after chemotherapy; to assess the nature of the lesion (fibrosis or residual disease), we subjected these patients to surgical restaging of the mediastinum: Results were negative in seven and positive in three. We conclude that open biopsy is indispensable to obtain good tissue specimens suitable for histologic and immunohistochemical assessment. Biopsy must be performed as a major surgical procedure to avoid reoperation: Mediastinoscopy and sternal splitting incisions proved the most reliable approaches. Locally radical or debulking resection might be considered in selected cases to enhance long-term results.