A significant proportion of patients with chronic ulcerative colitis will require an operation, particularly if the inflammatory process involves the entire colon and rectum. With the availability of newer surgical alternatives, the indications and timing for surgery of ulcerative colitis are being reevaluated. Growing evidence suggests that both low-grade and high-grade dysplasia are strong predictors of future malignancy. In the past, definitive treatment required total proctocolectomy and permanent ileostomy. In recent years, colectomy with ileal pouch-anal anastomosis has become the treatment of choice for most patients undergoing elective surgery for ulcerative colitis. Controversy has surrounded some technical aspects of the operation, including the necessity for rectal mucosal resection, the type of ileal pouch, and the need for a diverting ileostomy. Preservation of the anal transition zone with ileal pouch-distal rectal anastomosis should be applied with caution and with a proviso that life-time surveillance will be required. A majority of patients with Crohn's disease will also require at least one surgical procedure for this condition within their lifetime. Although controversial, it would appear that conservative principals should be applied to the surgical management of Crohn's disease of the small intestine and colon. Strictureplasty and balloon dilatation are being evaluated for the management of obstructing Crohn's disease. Ultrasound imaging techniques might be useful in preoperative and intraoperative evaluation of Crohn's disease and may help direct the extent of surgical resection. Endoscopic follow-up soon after ileocecal resection has demonstrated a high incidence of recurring inflammation in the preanastomotic area. Patients with Crohn's colitis appear to have a lower recurrence rate, although the optimum operation for their condition has not been clearly established. Most would agree that ileal pouch operations should be avoided in patients with frank Crohn's colitis, but may be applicable to patients with indeterminate colitis.