The surgical treatment of bone metastases is generally palliative. All operative procedures have to consider the mostly short life expectancy and therefore have to guarantee stability, early mobilization and short hospitalization. Surgery is absolutely indicated in patients with pathologic fractures of the long bones and innominate bone involving the hip joint, in patients with spinal lesions causing instability and progressive neural deficit and in patients with compression of peripheral nerves. Relative indications for surgery are given in cases where the risk of sustaining a pathologic fracture is high, in cases where spinal neurological deficit or root irritation can be expected, in patients where the tumor grows despite adequate irradiation or chemotherapy and finally in cases where open biopsy is useful to exclude primary malignant tumor or is necessary to define the further therapeutic management. As morbidity, hospitalization and complications increase in patients with pathologic fractures prophylactic stabilization is emphasized using well defined criteria. The standard surgical principles and techniques are presented and the results of 506 cases are reported.