Patients with ulcerative colitis (UC), especially those with a long-term standing or severe disease, show a higher incidence of colorectal neoplasms. Dysplasia represents the most important risk-factor for malignancy in patients with UC. From 1989 to 1999, 71 patients with UC, were surgically treated at our Institution. Indications for surgery were: non responding disease or refractory bleeding in 61; pathologic evidence of severe dysplasia during endoscopic surveillance in 5 patients, evidence of a neoplasm in the remaining 5 patients. Operative mortality was 1.4%. Infections of the surgical wound has been the most common postoperative complication. In 4 cases pouchitis has been reported. In 7 patients because of progression of the proctitis a second surgical treatment has been made. When surgical treatment is indicated in the course of ulcerative colitis, several operations may be performed. In the large majority of patients, total colectomy, mucosectomy and ileal pouch-anal anastomosis is the procedure of choice.