The diagnosis of a bone tumor is often an arduous task, even for the most experienced orthopedic pathologist. As a starting point, the classification of bone tumors is based on a histogenetic perspective encompassing the type of matrix produced (or not produced) by the tumor. In general, the surgical pathology report should include data pertinent to the treatment and prognostication of an individual patient, and the report should be delivered to the clinician in a clear, concise fashion. Reporting of most bone tumors is similar and includes such information as the type of surgery done, anatomic site, histological type and grade of the tumor (if applicable), and the adequacy of surgical margins. Special emphasis is needed for those tumors with distinct and well-established prognostic and therapeutic features such as osteosarcoma and Ewing's sarcoma/peripheral neuroectodermal tumor. Our recommendation emphasizes a standardized protocol for these sarcomas, especially in light of evidence that postchemotherapeutic tumor necrosis is of prognostic significance. It is also important to note that radiographic imaging plays a very important, often critical, role in allowing the pathologist the opportunity to reach the best final diagnosis. This is especially true when a malignant interpretation is contemplated and in subtyping lesions. We recommend close collaboration between musculoskeletal radiologists, clinicians, and pathologists when dealing with complicated neoplasms of bone. © 2004 Elsevier Inc. All rights reserved.