Abstract  This Classic Article is a reprint of the original work by Ernest Amory Codman, Registry of Bone Sarcoma: Part I.—Twenty-Five Criteria for Establishing the Diagnosis of Osteogenic Sarcoma. Part II.—Thirteen Registered Cases of “Five Year Cures” Analyzed According to These Criteria. An accompanying biographical sketch of Ernest Amory Codman, MD, and The Classic: The Registry of Bone Sarcomas as an Example of the End-Result Idea in Hospital Organization are available at DOIs 10.1007/s11999-009-1047-8 and 10.1007/s11999-009-1048-7, respectively. The Classic Article is ©1926 by the Journal of the American College of Surgeons and is reprinted with permission from Codman EA. Registry of bone sarcoma; part I, twenty-five criteria for establishing diagnosis of osteogenic sarcoma; part II, 13 registered cases of 5 year cures analyzed according to these criteria. Surg Gynecol Obstet. 1926;42:381–393.