A total of 32 patients with diverticulitis of right side of the colon were examined. They were 23 males and nine females with a mean age of 42.1 years. Of these 32 patients with initial diverticulitis, all patients received ultrasonography, 22 patients received computed tomography (CT), and 28 patients (87.5%) were diagnosed as having diverticulitis. Three patients with initial diverticulitis underwent an emergency operation, and the remaining 29 patients remitted conservatively. Five patients underwent enterectomy for treatment of initial diverticulitis. Of 27 patients with initial diverticulitis who did not undergo enterectomy, eight patients (29.6%) experienced recurrence of diverticulitis. A total of ten patients with initial and recurrent diverticulitis underwent an enterectomy for prevention of recurrence of diverticulitis. No recurrence of diverticulitis occurred in all the ten patients including two patients who had postoperative complications but remitted conservatively. Diverticulitis of right side of the colon was diagnosed by ultrasonography and CT with a high diagnosing rate, that contributed to avoid unnecessary emergency operation. In the vast majority of cases, diverticulitis of right side of the colon is relieved conservatively, but often recurs. These patients should be strictly followed up.