Although the morbidity and mortality after colectomy for sigmoid diverticulitis has been estimated in France, few data are available on medium- and long-term outcomes. This multicentre observational and analytical study aimed to determine the prevalence of surgical complications beyond the 90th postoperative day. From the EDI-VERTICULITE database, 1441 patients operated on between January 2010 and July 2021 were included. The objectives were to describe the prevalence of surgical complications (postoperative ventration; bowel obstruction; non-closure of stoma and recurrence of diverticulitis) and their respective independent risk factors. A mixed logistic regression model with a random effect was used to account for a possible centre effect. With a mean follow-up of 2106±1239 days, 39.3% of all patients and 27% of elective patients presented with at least one late complication. Eventration and non-closure of the stoma were the two most frequent complications. The main independent risk factors were the patient's condition (advanced age, overweight, obesity, ASA score≥3) and operative characteristics (conversion to laparotomy and 2-stage surgery) in the whole cohort of patients, and two-stage surgery and the occurrence of severe postoperative complications in the subgroup of patients operated on electively. Late complications may occur in 27 to 40% of patients after diverticular surgery, mainly in the first year. Although these results need to be confirmed in a prospective study, it would seem important to inform patients of this when discussing the indication for prophylactic colectomy.