Diverticulitis is classified as uncomplicated or complicated, i.e., associated with perforation, fistula, or obstruction. CT allows more reliable characterization of an acute attack of diverticulitis. Medical management is reserved for uncomplicated diverticulitis and the initial phase of treatment of diverticulitis associated with abscess formation. Percutaneous abscess drainage is a major advance, which permits one-stage resection in a majority of cases. Diverticulitis associated with free perforation can be selectively managed with resection and primary anastomosis, although a Hartmann resection is likely to be performed. A fistula associated with diverticulitis can usually be managed with a one-stage resection. Obstruction can be managed selectively with resection with on-table bowel preparation, primary anastomosis, and proximal diversion. Laparoscopic techniques permit successful performance of elective resections most of the time. Hand assistance is of particular value when the patient has dense fibrosis.