PURPOSE: With the gradual changes in diet pattern, the incidence of diverticular disease have progressively increased. The diverticular disease including diverticulitis is difficult to diagnose prior to the operation as it mimics common acute abdominal conditions like acute appendicitis. Also, controversies abound as regards the optimal treatment, ranging from conservative treatment to colon resection. The aim of the present paper was to review diagnosis and treatment strategy followed by a clinical appraisal. METHODS: We studied retrospectively 101 patients who were diagnosed as colonic diverticulitis for 10 years period between January, 1991 and December, 2000 at Seoul Red Cross Hospital, Dept. of Surgery. RESULTS: There were 59 males and 42 females. The male to female ratio was 1.4 : 1. During admission, everyone complained abdominal pain as an initial symptom, especially on the right lower quadrant. The right colon was the most common site with single diverticulitis. The diagnosis of diverticulitis was performed by ultrasonography, CT scan, and colon study, barium enema, colonofiberscopy except in 17 cases which were diagnosed preoperatively having appendicitis. Two treatment groups were identified. Group I (n=48) received conservative treatment with or without appendectomy, while group II (n=53) underwent definitive surgery. Overall, there was no difference in clinical outcome except for the duration of antibiotics between two groups. CONCLUSIONS: In treating uncomplicated diverticulitis, the conservative treatment should be considered at first. Conservative treatment with systemic antibiotics have resulted in a comparable outcome to that of the surgical group with low morbidity and low recurrence rate. Therefore, without serious complications such as hemorrhage, fistula, septic condition, inability to exclude carcinoma, clinical deterioration, young age, right colon diverticulitis, chronic stricture or the use of steroid, we propose that a conservative approach be adopted.