OBJECTIVES: Surgical resection and anastomosis is the standard of care for many colon and rectal pathologies. Postoperative anastomotic leak is a major complication of these procedures and results in a significant burden to the healthcare system. The goal of this literature review is to identify the rate of postoperative anastomotic leaks and the factors associated with their occurrence.  METHODS: Predetermined search terms were used to systematically identify articles that referred to postoperative leaks in left colon and rectal resection surgery from January 1st, 2003 to August 8th, 2015 (using the PubMed database). Individual case studies, conference abstracts, letters to the editor, expert opinion without original or other supporting empiric evidence, and editorials were excluded. References from the identified articles were cross-referenced to ensure that no major articles were excluded. Each abstract was reviewed by two trained, independent reviewers.  RESULTS: Forty-nine published articles met the final criteria for inclusion. Pooled data yielded a mean post-operative anastomotic leak rate of 5.96% (range .4-19.2%). Nineteen articles reported on the mean, median and/or range of post-operative days (PODs) when the leak developed. The first diagnosis of the post-operative leak was 10.6 PODs (weighted mean) from the date of surgery. The most commonly reported patient risk factors were males between the ages of 60-70, cigarette smoking, and having a BMI > 25. Most common medical risk factors were tumor and/or anastomosis location. Procedural risk factors included approach for anastomosis creation (stapled vs. sewn): patients receiving stapled anastomosis were less likely to develop postoperative anastomotic leak.  CONCLUSIONS: The rate of postoperative anastomotic leak reported in this review is lower than the rates that have been reported earlier. This may be attributed to improved surgical technique and the availability of improved equipment, such as stapling devices, used to create the anastomoses.