The aim of this study wasto assess risk factors of mortality after unplanned surgery following colorectal resection. All the consecutive patients who underwent colorectal resection between 2011 and 2020 in a French national cohort were retrospectively included. Perioperative data of the index colorectal resection (indication, surgical approach, pathological analysis, postoperative morbidity), and characteristics of unplanned surgery (indication, time to complication, time to surgical redo) were assessed in order to identify predictive factors of mortality. Among 547 included patients, 54 patients died (10%; 32 men; mean age = 68 ± 18years, range 34-94years). Patients who died were significantly older (75 ± 11 vs 66 ± 12years, p = 0.002), frailer (ASA score 3-4 = 65 vs 25%, p = 0.0001), initially operated through open approach (78 vs 41%, p = 0.0001), and without any anastomosis (17 vs 5%, p = 0.003) than those alive. The presence of colorectal cancer, the time to postoperative complication and the time to unplanned surgery were not significantly associated to the postoperative mortality. After multivariate analysis, 5 independent predictive factors of mortality were identified: old age (OR 1.038; IC 95% 1.006-1.072; p = 0.02), ASA score = 3 (OR 5.9, CI95% 1.2-28.5, p = 0.03), ASA score = 4 (OR 9.6; IC95% 1.5-63; p = 0.02), open approach for the index surgery (OR 2.7; IC95% 1.3-5.7; p = 0.01), and delayed management (OR 2.6; IC95% 1.3-5.3; p = 0.009). After unplanned surgery following colorectal surgery, one out of 10 patients dies. The laparoscopic approach during the index surgery is associated with a good prognosis in the case of unplanned surgery.