Forty-three cases of primary retroperitoneal sarcomas, observed and treated from 1970 to 1983 at this Institute, were analysed. The series consisted of 16 liposarcomas (37%), 10 leiomyosarcomas (23%), 7 rhabdomyosarcomas (16%), 5 fibrosarcomas (12%), 2 malignant histiocytomas (5%), 2 sarcomas NOS (5%) and 1 mesenchymoma (2%). All the patients underwent surgery. In order to evaluate the results of surgery, the patients were divided into three groups, according to the type of operation performed, that is open biopsy, resection and excision. Survival of the patients in the first group never exceeded 24 months. The symptom-free period for the patients treated by incomplete removal of the tumour (second group) lasted 3-24 months. Further surgery, in three cases for this group, did not result in a useful control of the disease. As regards radically treated cases, local recurrence was observed in 3 of the 7 liposarcomas, 2 of the 5 leiomyosarcomas, 1 of the 2 rhabdomyosarcomas and 1 fibrosarcoma. Out of 16 cases of the third group, regularly followed up, only 3 patients (liposarcomas) were alive and free of disease at 5 years from first operation. Overall 5-year survival for this group was 31.9%; disease-free survival was 18.7%. For the whole series of 43 cases, overall 5-year survival was 11.4%. As far as histology was concerned, liposarcomas showed the highest operability rate: out of 16, 7 were resected and 9 radically excised. There is a lack of convincing evidence for the utility of post-operative chemotherapy. On the contrary, post-operative radiotherapy seems to be worthwhile for liposarcomas, especially after non-radical operations.