Three cases of acute diverticulitis of the right colon are described and a review of the international literature about this rare disease is made. Diverticulitis of the ascending colon is an uncommon disease which mimics appendicitis or perforated neoplasm. The correct diagnosis is rarely made, but can be suggested by signs and symptoms and confirmed by the barium enema. It should be treated conservatively, like left-colon diverticulitis. Isolated diverticula can be managed by simple excision and primary closure. Local resection may be necessary if the involved area is too large. Right hemicolectomy is performed when carcinoma is strongly suspected.