Objective To improve and evaluate the diagnosis and treatment of retroperitoeal fibrosis. Methods From February 1975 to December 2001, 36 cases (male: 20, female: 16) of retroperitoneal fibrosis were treated, 12 of whom were primary fibrosis and 10 were secondary to malignant tumors and the others were secondary to radiotherapy of malignant tumors. Surgical intervention was undertaken in 28 patients with preoperative and postoperative administration of corticosteroids. Results The patients were followed up for 6 to 42 months with improved or normal renal function. Most of them had very good results. Death secondary to malignancy was found in 4 cases. Conclusion To relieve the obstruction due to hydronephrosis by surgical intervention is very effective in treatment of retroperitoneal fibrosis.