Fifty-one patients with retroperitoneal sarcoma underwent surgery at the University Clinics of Hamburg from 1970 to 1988. Malignant schwannoma, liposarcoma and malignant fibrous histiocytoma were the most common histological types. High grade sarcomas (G3) predominated (42%), while 26% were graded G2 and 33% G1. Complete resection was possible in 59% of cases. Reoperation for local recurrence and debulking in case of not completely resectable disease was common. Regional lymph node metastasis was found in 20% of cases. The peritoneum was the preferred location of metastatic spread. All adjuvant chemotherapies were followed by tumour recurrences. After adjuvant radiotherapy three of six patients remained free of disease. In cases of residual tumour we observed few partial responses on chemo- and radiotherapy, and all patients died because of the disease. The mean survival time was 60 months, the 5- and 10-year survival rates were 35% and 15%, respectively. Factors influencing prognosis in univariate analysis included grade, size, resectability, presence of metastatic spread, histological type, microscopic local growth (infiltrative vs intact pseudocapsule of fibrous tissue) and local recurrence. With multivariate analysis grade, size and lymph node metastasis retained their prognostic significance.