The objective of this study was to compare the anastomotic leak rates between powered and manual circular staplers in elective left-sided colorectal resections. A retrospective cohort study of elective left-sided colorectal resections before and after implementation of a powered circular stapler at a tertiary care center was conducted. The manual stapler group consisted of consecutive resections performed between January 2016 to December 2016 and the powered stapler group, between September 2021 and December 2022. Primary outcome was 30-day anastomotic leak rate. A chi-squared analysis was performed to compare anastomotic leak rates. Factors associated with anastomotic leak were examined. Two-hundred forty-seven patients were included: 154 in the manual stapler group and 93 in the powered stapler group. Mean (SD) age was 60 (15) years old, 37.7% were female and 72.9% of resections were performed for malignancy. Both groups had similar patient characteristics and surgical technique. Overall leak rate was 2.0% in the manual stapler group and 10.8% in the powered stapler group. The powered staplers were found to have 6.06 times the odds of leak compared to manual staplers (95% CI, 1.62-22.65; p = 0.01). None of the other factors were found to be associated with anastomotic leak. Patients who had left-sided colorectal anastomosis had higher anastomotic leak rates with powered compared to manual circular staplers. This finding is contrary to previous retrospective studies that found lower leak rates with powered staplers.