Purpose The present study assessed the factors associated with the maintenance of a functional anastomosis in a large consecutive series of patients with anastomotic leakage (AL). Methods All consecutive patients presenting with AL after colorectal or coloanal anastomosis (2012–2019) were analyzed. The primary end point was a functional anastomosis without a stoma at 1 year. Results A total of 156 patients were included. AL was initially treated by antibiotics (38%), drainage (43%) or urgent surgery (19%). Initial treatment of AL was not adequate in 24.3%, and reintervention in the form of drainage or surgery was required. A total of 60.9% of patients had a functional anastomosis without a stoma 1 year after surgery. Factors associated with the risk of anastomotic failure at 1 year were diabetes (odds ratio [OR] = 4.24 [95% confidence interval {CI} 1.39–14.24] p = 0.014), neoadjuvant chemoradiotherapy (OR = 3.03 [95% CI 1.14–8.63] p = 0.03) and Grade B (OR = 6.49 [95% CI 2.23–21.74] p = 0.001) or C leak (OR = 35.35 [95% CI 9.36–168.21] p < 0.001). Among patients treated initially by drainage, side-to-end or J-pouch anastomoses were significantly associated with revision of the anastomosis compared to end-to-end (OR = 12.90, p = 0.04). Conclusion After acute AL following coloanal or colorectal anastomosis, 60.9% of patients had a functional anastomosis without a stoma at the 1 year of follow-up. The type of treatment of AL influenced the risk of anastomotic failure.