&NA;The patterns of presentation and associated treatments of 65 patients with acute perforated diverticulitis of the left colon have been reviewed. Four types of operations were identified: primary resection with anastomosis (group I, N=29), primary resection with anastomosis and protective colostomy (group II, N=5), primary resection with Hartmann procedure (group III, N=26), and delayed resection three‐staged procedure (group IV, N=5). The severity of disease was also classified (stages I to IV). Postoperative mortality rates in the first two groups were lower than that of the Hartmann group (3.4 vs. 15.3 percent). The mean length of initial hospitalization was 16±1.2 days for group I, 18.2±4.4 days for group II, 19.4±2 days for group III, 26.4±4.4 days for group IV (P<.05,t‐test group IVvs.groups I, II, and III). Complications in the Hartmann group were high with a 23 percent wound infection rate and mortality after closure of colostomy and bowel reconstruction was 3.8 percent. These data demonstrate that primary resection with anastomosis is a satisfactory operation for the majority of patients with perforated diverticulitis (stages I to III), and there appears to be no clinical indication to use the three‐staged operation.