Background: Anastomotic leakage (AL) significantly impairs short-term outcomes. The impact on the long-term outcomes remains unclear. This study aimed to identify the risk factors for AL and the impact on long-term survival in patients with left-sided colorectal cancer.Methods: Nine-hundred patients with left-sided colorectal carcinoma who underwent sigmoid or rectal resection were enrolled in the study. Risk factors for AL after sigmoid or rectal resection were identified and long-term outcomes of patients with and without AL were compared.Results: AL rates following sigmoid and rectal resection were 5.1% and 10.7%, respectively. Higher ASA score (III-IV; OR=10.54, p=0.007) was associated with AL in patients undergoing sigmoid surgery on multivariable analysis. Male sex (OR=2.40, p=0.004), CCI score >5 (OR=1.72, p=0.025) and T3/T4 stage tumors (OR=2.25, p=0.017) were risk factors for AL after rectal resection on multivariable analysis. AL impaired disease-free and overall survival in patients undergoing sigmoid (p=0.009 and p=0.001) and rectal (p=0.003 and p=0.014) surgery.Conclusion: ASA score of III-IV is an independent risk factor for AL after sigmoid surgery and male sex, higher CCI score, and advanced T stage are risk factors for AL after rectal surgery. AL impairs the long-term survival in patients undergoing left-sided colorectal surgery.