Purpose: The purpose of this study is to determine whether treating peri-operative anaemia with iron infusion has an association with overall survival and recurrence-free survival in colorectal cancer (CRC) patients. Methodology Data from patients who underwent CRC surgery at Lyell McEwin Hospital – Northern Adelaide Local Health Network – Australia was retrospectively collected. Ethic approval with waiver of consent was obtained from the local ethics committee. Results From January 2017 to December 2020, there were 385 surgical CRC patients, of whom 33.78% had anaemia (defined as Hb<13g/l in males and <12g/l in females). Iron studies were performed in 291 (78.65%) patients, showing 73 patients with both anaemia and suspected iron deficiency (low serum iron level and preoperative ferritin < 50ug/l). 58 patients (15.68%) received preoperative iron infusion and 120 (33.43%) received iron postoperatively. Anaemia at any stage of operation was a risk of death and longer length of hospital stay (p<0.001). No significant difference was found in death, morbidity, anastomotic leak, cancer recurrence and readmission within 30 days between patients with and without iron infusion. Preoperative iron infusion could not reduce the rate of postoperative blood transfusion but the change in Hb level postoperative and preoperative was lowest in patients with preoperative iron infusion (median 10g/l, p < 0.001). Conclusion Although this cohort showed no significant difference in overall outcomes between patients with and without iron infusion, preoperative seemed to have positive effects, providing primary data for a clinical trial of preoperative iron infusion in CRC patients with anaemia and iron deficiency.