This study compared laparoscopic with open sigmoid colectomy for patients with a diagnosis of diverticulitis. Increased use of less invasive techniques makes it vitally important to evaluate outcomes of these techniques as compared with standard open procedures. Patients undergoing sigmoid colectomy for diverticulitis without hemorrhage (code 56211) between January 1997 and December 2001 were reviewed. Two groups were identified: those undergoing open sigmoid colectomy and those undergoing laparoscopic sigmoid colectomy; American Society of Anesthesiologists (ASA) scores, operative time, intensive care unit (ICU) and hospital length of stay, morbidity/mortality, and hospital charges were compared. During the study period 271 sigmoid colectomies were performed for diverticulitis without hemorrhage: 56 laparoscopically and 215 with the standard open technique. Four patients required conversion from laparoscopic to open colectomy. Mean ASA scores were: open group 2.4; laparoscopic group, 1.9 (P < 0.001). Mean operative times were: laparoscopic group, 170 +/- 45 minutes; open group, 140 +/- 49 minutes (P < 0.001). In the open group 39 patients required transfer to the ICU; one patient in the laparoscopic group required transfer to the ICU. Average hospital lengths of stay for the open and laparoscopic groups were 9.06 and 4.12 days, respectively (P < 0.001). Complications were recorded in 57 (27%) of 215 patients who underwent an open procedure versus 5 (9%) of 56 patients who underwent laparoscopic sigmoid colectomy (P < 0.01). There were three deaths in the open group and none in laparoscopic group. Average total hospital charges were 25,700 dollars for open sigmoid colectomy and 17,414 dollars for laparoscopic colectomy. Laparoscopic sigmoid colectomy compares favorably with open sigmoid colectomy for patients with a diagnosis of diverticulitis.