A surgical staging system for musculoskeletal sarcomas stratifies bone and soft-tissue lesions of any histogenesis by the grade of biologic aggressiveness, by the anatomic setting, and by the presence of metastasis. The three stages: I--low grade; II--high grade; and III--presence of metastases, are subdivided by (a) whether the lesion is anatomically confined within well-delineated surgical compartments, or (b) beyond such compartments in ill-defined fascial planes and spaces. Operative margins are defined as intralesional, marginal, wide, and radical, and relate the surgical margin to the lesions, its reactive zone, and anatomic compartment. The system defines prognostically significant progressive stages of risk which also have surgical implications. When the system is linked to clearly defined surgical procedures, it permits appropriate evaluation and comparison of the new treatment protocols designed to replace standard surgical treatment.