To determine the safety and feasibility of primary resection and anastomosis with or without a diverting stoma, as compared to Hartmann's procedure, for patients with acute complicated sigmoid diverticulitis. MEDLINE was searched for studies and trials conducted between 1966 and December 2003. This search revealed trials comparing primary resection and anastomosis to Hartmann's procedure. The term "diverticulitis, colonic" with the sub-heading "surgery" was used and the search was limited to human studies and clinical trials. Additional studies were found using the MeSH terms: "surgical procedures, operative", "surgical anastomosis", and "Hartmann procedure", combined with the term "diverticulitis, colonic". The author also searched EMBASE and the Cochrane database for clinical trials using similar terminology. No language restrictions were applied. Eighteen studies met the inclusion criteria and reported 884 patients with acute complicated diverticulitis. None of these studies were randomised; it is likely that there was a significant degree of selection bias. No significant differences were found between primary resection with anastomosis and Hartmann's procedure with respect to mortality, morbidity, sepsis, wound complications and duration of procedure and anti-biotic treatment. Some studies found that primary anastomosis and a protecting stoma, with or without intra-operative colonic lavage, have more favourable results than Hartmann's procedure. This review suggests that surgical resection and primary anastomosis in acute diverticulitis with peritonitis compares favourably with Hartmann's procedure in terms of peri-operative complications. The need for revision of Hartmann's procedure could be subsequently avoided. Some articles showed that patients with severe peritonitis, who had a diverting stoma, in the setting of resection and primary anastomosis, had the lowest complication rate. However, the quality of these studies was poor with the presence of selection bias.