Sarcomas constitute a complex and diverse family of rare, clinicopathologically distinct malignant neoplasms of mesenchymal cell origin. The annual incidence of soft tissue sarcomas in the United States for 2004 is estimated to be about 8,680 cases, with an overall mortality rate of approximately 3,660 cases per year, including adults and children. The expertise of the NCCN institutions allows the panel to use their extensive experience in defining these consensus practice guidelines for the management of patients with sarcomas. These guidelines address sarcoma management from the perspective of four disease subtypes: soft tissue extremity sarcomas, retroperitoneal (including nongastrointestinal visceral) sarcomas, gastrointestinal stromal tumors and other intra-abdominal sarcomas, and the unique mesenchymal neoplasm known as desmoid tumor (or desmoid aggressive fibromatosis). © Journal of the National Comprehensive Cancer Network.