Soft-Tissue Retroperitoneal Sarcomas (STRP) are rare tumors. Late diagnostic and extreme technical difficulties to obtain total resection with margins free of tumor, are associated to a high relapse rate. Eighteen patients with STRP were retrospectively reviewed, evaluating: Clinical onset, histology, treatment-type performed, mortality and survival rate. Total resection was performed in eleven patients (61%), with inclusion of neighbor organs or structures in five of them (45%). In one case partial exeresis associated with left hemicolectomy was done, and only biopsy was performed in six cases. After total exeresis, seven patients showed local relapse (64%) and four of these patients (57%) underwent surgery again. Global surgery mortality was one patient. Survival at five years in resected patients was 57%. In patients with biopsy only, mean survival was 16.6 months, patients with total or partial resection, survival was 79.1 months. An aggressive surgical approach, with tumor total exeresis and a block resection of neighbor affected organs or structures, is the best alternative in the treatment of STRP.