['Recent evidence raises concern about the use of perioperative non-steroidal anti-inflammatory drug (NSAID) use after colorectal resection. The purpose of this retrospective cohort study was to investigate the relationship between perioperative ketorolac use and anastomotic leakage after colorectal surgery.', 'A retrospective review (2004-2011) was performed on patients who underwent elective colorectal surgery. Univariate analysis and multivariate logistic regression were used to evaluate the association between patients who did not receive any NSAIDs and those who received ketorolac within the first 5 days perioperatively and leak rate.', 'A total of 731 patients were identified as having resection with primary anastomosis: 376 (51.4 %) received no NSAIDs and 355 (48.6 %) received ketorolac perioperatively within 5 days after their surgery. There were 24 (3.3 %) leaks, with 12 in both the no NSAIDs (3.2 %) and ketorolac (3.4 %) groups, odds ratio (OR) 1.06 (0.43, 2.62; p = 0.886). Adjusting for smoking, steroid use, and age, there remained no significant difference between ketorolac use and leakage, OR 1.21 (0.52, 2.84; p = 0.660). In our multivariate model, only smoking was a significant predictor of postoperative leak, OR 3.34 (1.30, 8.62; p = 0.021).'] Are perioperative nonselective non-steroidal anti-inflammatory drugs associated with anastomotic leakage after colorectal surgery?