© The ASCRS 2017. BACKGROUND: The management of the rectal wall defect after local excision of rectal neoplasms remains controversial, and the existing data are equivocal. OBJECTIVE: This study aimed to determine the effect of open versus closed defects on postoperative outcomes after local excision of rectal neoplasms. DESIGN: Data from 3 institutions were analyzed. Propensity score matching was performed in one-to-one fashion to create a balanced cohort comparing open and closed defects. SETTINGS: This study was conducted at high-volume specialist referral hospitals. PATIENTS: Adult patients undergoing local excision via transanal endoscopic surgery from 2004 to 2016 were included. Patients were assigned to open- and closed-defect groups, and further stratified by full- or partial-thickness excision. INTERVENTION: Closure of the rectal wall defect was performed at the surgeon's discretion. MAIN OUTCOME MEASURES: The primary outcome measured was the incidence of 30-day complications. RESULTS: A total of 991 patients were eligible (593 fullthickness excision with 114 open and 479 closed, and 398 partial-thickness excision with 263 open and 135 closed). After matching, balanced cohorts consisting of 220 patients with full-thickness excision and 210 patients with partial-thickness excision were created. Operative time was similar for open and closed defects for both fulland partial-thickness excision. The incidence of 30-day complications was similar for open and closed defects after full- (15% vs. 12%, p = 0.432) and partial-thickness excision (7% vs 5%, p = 0.552). The total number of complications was also similar after full- or partialthickness excision. Patients undergoing full-thickness excision with open defects had a higher incidence of clinically significant bleeding complications (9% vs 3%, p = 0.045). LIMITATIONS: Data were obtained from 3 institutions with different equipment and perioperative management over a long time period. CONCLUSIONS: There was no difference in overall complications between open and closed defects for patients undergoing local excision of rectal neoplasms, but there may be more bleeding complications in open defects after full-thickness excision. A selective approach to defect closure may be appropriate.