BACKGROUND The aim of the study was to improve the diagnosis and treatment of retroperitoneal schwannoma by analysing clinical manifestations and postoperative course of this rare disease. METHODS A retrospective analysis of 82 patients with retroperitoneal schwannoma between January 1951 and September 2004 was carried out. RESULTS The patients were 38 (46%) men and 44 (54%) women between the ages of 6 months and 70 years. The interval between clinical manifestation and diagnosis ranged from 10 days to 2 years. The main symptoms were abdominal distension (30.5%) and abdominal pain (20.7%). Only in 13 patients (15.9%) a correct preoperative diagnosis was made by either ultrasound-guided biopsy, computed tomography scanning or magnetic resonance imaging. All patients received operative therapy. Sixty patients (73.2%) underwent a total resection; 13 patients (15.9%) subtotal resection, but 9 patients (11.0%) had only an examination and a biopsy. Two patients (2.4%) had multiple schwannomas and two others had a simultaneous malignancy (adenocarcinoma of the ascending colon and squamous-cell carcinoma of the lung, respectively). Most of the retroperitoneal schwannomas were close to the spine. Pathological results showed 81 (98.8%) were benign schwannoma and 1 (1.2%) was a malignant one. The tumour size ranged from 3 to 22 cm. One benign schwannoma recurred 3 years after the operation. The patient with malignant schwannoma died 18 months after the operation because of metastasized disease. CONCLUSION Most of the retroperitoneal schwannomas are benign. It is difficult to make an accurate preoperative diagnosis. However, with the preoperative assessment of ultrasound-guided fine-needle aspiration, computed tomography and magnetic resonance imaging, the accuracy of diagnosis could definitely be improved. Treatment depends solely on surgery. Malignant schwannomas are insensitive to chemotherapy and radiation, resulting in poor prognosis.