© 2014, The Society for Surgery of the Alimentary Tract. Background: Stoma reversals (SRs) are commonly performed with potentially significant postoperative complications including surgical site infections (SSIs). Our aim was to determine the incidence and risk factors for SSIs in a large cohort of SR patients.Design: We reviewed our institutional 2006–2011 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database for 30-day SSIs in patients undergoing SR. Records were additionally reviewed for 10 non-ACS-NSQIP variables. The primary outcome was SSI after SR. Secondary outcomes were additional 30-day postoperative complications and length-of-stay. Predictors of SSIs were identified using multivariable logistic regression.Results: From 528 SR patients, 36 patients developed a SSI (6.8 %). Most patients underwent SR for loop ileostomies (76.5 %) after index operations for ulcerative colitis (38.6 %) and colorectal cancer (27.8 %). SSI patients had fewer subcutaneous drains compared to patients with no SSI and had significantly higher rates of smoking, ASA 3–4 classification and laparotomies at SR (p < 0.05). Patients with SSI had increased length-of-stay and 30-day morbidities including sepsis and returns to the operating room (p < 0.05) compared to no-SSI patients. On multivariable analysis, subcutaneous drain placement was suggestive of SSI protection (odds ratio [OR] 0.52, 95 % confidence interval [CI] 0.2–1.1), but only smoking was significantly associated with an increased risk for SSI (OR 2.4, 95 % CI 1.1–5.4).Conclusions: Smoking increased the risk of SR SSIs in patients by over twofold, and SR SSIs are associated with additional significant morbidities. Smoking cessation should be an important part of any SSI risk-reduction strategy.