Retroperitoneal sarcomas are a rare and highly malignant group of tumors. Because of their anatomical location, they often reach a large size before detection and are difficult to diagnose clinically because of nonspecific symptoms. After surgical resection, the tumors display a high rate of recurrence, thus requiring long-term and often indefinite follow-up. Consequently, imaging plays a central role in the diagnosis and management of these tumors. This review article examines the epidemiology, staging criteria, histologic subtypes, diagnosis, treatment, and general imaging principles for all retroperitoneal sarcomas, with detailed focus on the most common subtype, retroperitoneal liposarcomas.