Retroperitoneal sarcomas (RPS) are rare tumors, accounting for approximately 15% of soft tissue sarcomas. Surgical resection of localized tumors with gross and microscopically negative margins remains the standard of care. However, because RPS are frequently large and locally advanced, resections are often incomplete, resulting in local recurrence. Investigators are evaluating combined-modality therapies to improve local control and disease-specific survival. This review outlines current concepts and evolving treatment strategies in the diagnosis, staging, and management of RPS. J. Surg. Oncol. 2006;94:81–87. © 2006 Wiley-Liss, Inc.