ObjectiveTo analyze risk factors of postoperative complications associated with reversal of defunctioning ileostomy in patients with rectal cancer undergoing sphincter preservation surgery. MethodData were collected retrospectively for consecutive patients undergoing defunctioning ileostomy following sphincter preservation surgery for rectal cancer, from January 2014 to December 2014. ResultsOne hundred and thirty patients were included (median time to reversal 132 d, range 39-692 d), of whom 35 patients (26.92%) had postoperative complications after stoma reversal. The main complications included 23 cases of diarrhea, 6 cases of bowel obstruction, 9 cases of incision infection, and 4 cases of perianal eczema. The results of univariate analysis showed that the distant of tumor from anal verge <5 cm (P=0.010), postoperative adjuvant chemotherapy (P=0.002), and time to reversal (P=0.025) were related to the postoperative complications associated with reversal of defunctioning ileostomy in patients with rectal cancer undergoing sphincter preservation surgery. The result of multivariate analysis by using a logistic regression model showed that the time to reversal (OR=1.006, P=0.021) was a significant independent risk factor for it. ConclusionDelay reversal of defunctiong ileostomy might increase risk of postoperative complications associated with reversal of defunctioning ileostomy in patients with rectal cancer undergoing sphincter preservation surgery.