Sixteen years experience (1974-1989) is recorded with the treatment of 18 patients with retroperitoneal sarcoma. The tumor was palpable in all. Four syndromes could be differentiated in these patients: gastrointestinal, renal, vascular and neurologic. All modern methods of diagnosis were applied: ultrasonography in 12 patients, computer tomography--13, angiography--3, X-ray examination of the gastrointestinal tract--7, gamma-renography--5, urography--2. Radical operative intervention is considered treatment of choice, followed by radio- or hemotherapy. Radical extirpation of the tumor was performed in 10 patients (55.5 per cent). Extended operative interventions with resection of adjacent organs were performed in 4 patients (22.2 per cent). After histologic verification 10 patients (55.5 per cent) were subjected to chemotherapy and 7 to radiotherapy. Postoperative case fatality rate was 17 per cent (3 patients died). Four patients 22.2 per cent) had relapse of the tumor between the first and the third year.