About 7 percent of patients who have resections for diverticular disease later suffer from recurrent disease. In resections for sigmoid disease, the surgeon often has the choice of using either the distal sigmoid colon or the upper rectum for the distal portion of the anastomosis. We examined the courses of 501 consecutive patients who had resection and anastomosis for diverticular disease at the Mayo Clinic between 1970 and 1975. Recurrent diverticulitis developed in 12.5 percent of the patients in whom the sigmoid colon had been used for the distal margin of anastomosis and in 6.7 percent of those in whom the rectum had been used (p = 0.03). Reoperation was required in 3.4 percent of the patients in whom the sigmoid colon was used as the distal anastomotic site and in 2.2 percent of those in whom the rectum had been used (p greater than 0.05). We found no increase in anastomotic leaks or other perioperative complications in patients in whom the rectum had been mobilized. We conclude that the entire distal sigmoid colon should be removed during resection for diverticular disease and anastomosed to the upper rectum to avoid recurrent diverticulitis.