Background: Perioperative care multimodal protocol significantly improve outcome in surgery. Aim: To investigate risk factors to various endpoints in patients submitted to elective colorectal operations under the ACERTO protocol. Methods: Cohort study analyzing through a logistic regression model able to assess independent risk factors for morbidity and mortality, patients submitted to elective open colon and/or rectum resection and primary anastomosis who were either exposed or non-exposed to demographic, clinical, and ACERTO interventions. Results: Two hundred thirty four patients were analyzed and submitted to 156 (66.7%) rectal and 78 (33.3%) colonic procedures. The length of hospital postoperative stay (LOS) ≥ 7 days was related to rectal surgery and high NNIS risk index; preoperative fasting ≤4 h (OR=0.250; CI95=0.114-0.551) and intravenous volume of crystalloid infused > 30ml/kg/day (OR=0.290; CI95=0.119-0.706). The risk of postoperative site infection (SSI) was approximately four times greater in malnourished; eight in rectal surgery and four in high NNIS index. The duration of preoperative fasting ≤4 h was a protective factor by reducing by 81.3% the risk of surgical site infection (SSI). An increased risk for anastomotic fistula was found in malnutrition, rectal surgery and high NNIS index. Conversely, preoperative fasting ≤4 h (OR=0.11; CI95=0.05-0.25; p<0.0001) decreased the risk of fistula. Factors associated with pneumonia-atelectasis were cancer and rectal surgery, while preoperative fasting ≤ 4 h (OR=0.10; CI95=0.04-0.24; p<0.0001) and intravenous crystalloid ≤ 30 ml/kg/day (OR=0.36; CI95=0.13-0.97, p=0.044) shown to decrease the risk. Mortality was lower with preoperative fasting ≤4 h and intravenous crystalloids infused ≤30 ml/kg/day. Conclusion: This study allows to conclude that rectal procedures, high NNIS index, preoperative fasting higher than 4 h and intravenous fluids greater than 30 ml/kg/day during the first 48 h after surgery are independent risk factors for: 1) prolonged LOS; 2) surgical site infection and anastomotic fistula associated with malnutrition; 3) postoperative pneumonia-atelectasis; and 4) postoperative mortality.