THERE has been increasing interest in cecal diverticulitis since the first case was reported by Portier1in 1912. Since that time, however, no distinction between diverticulitis of the cecum and diverticulitis of the ascending colon has been made in the literature. In a recent paper we separated these two entities and stressed cecal diverticulitis.2The differences between them are sufficient to warrant this presentation. Up to the present there have been 14 reported cases of diverticulitis of the ascending colon.3To this number we are adding two cases. The pitfalls in the analysis of a limited number of cases are apparent. INCIDENCE According to some investigators,4the incidence of diverticula of the large bowel varies from 3.0 to 6.9%. Only 1.5 to 2.0% of these diverticula are recorded as occurring in the right half of the colon. It is difficult to state accurately the occurrence rate