Hypothesis: Enterotomy or unplanned bowel resection (EBR) may occur during elective incisional hernia repair (IHR) and significantly affects surgical outcomes and hospital resource use. Design: Retrospective review of patients undergoing IHR between January 1998 and December 2002. Setting: Sixteen tertiary care Veterans Affairs medical centers. Patients: A total of 1124 elective incisional hernia repairs identified in the National Surgical Quality Improvement Program data set. Intervention: Elective IHR. Main Outcome Measures: Thirty-day postoperative complication rate, return to operating room, length of stay, and operative time. Results: Of the 1124 elective procedures, 74.1% were primary IHR, 13.3% were recurrent prior mesh IHR, and 12.6% were recurrent prior suture. Overall, 7.3% had an EBR. The incidence of EBR was increased in patients with prior repair: 5.3% for primary repair, 5.7% for recurrent prior suture, and 20.3% for prior mesh repair (P<.001). The occurrence of EBR was associated with increased postoperative complications (31.7% vs 9.5%; P<.001), rate of reoperation within 30 days (14.6% vs 3.6%; P<.001), and development of enterocutaneous fistula (7.3% vs 0.7%; P<.001). After adjusting for procedure type, age, and American Society of Anesthesiologists class, EBR was associated with an increase in median operative time (1.7 to 3.5 hours; P<.001) and mean length of stay (4.0 to 6.0 days; P<.001). Conclusions: Enterotomy or unplanned bowel resection is more likely to complicate recurrent IHR with prior mesh. The occurrence of EBR is associated with increased postoperative complications, return to the operating room, risk of enterocutaneous fistula, length of hospitalization, and operative time. ©2008 American Medical Association. All rights reserved.