Optimising preoperative haemoglobin (Hb) before elective surgery is recommended by the National Institute of Clinical Excellence. We have used a quality improvement (QI) approach to treat iron deficiency anaemia in patients presenting to the preoperative assessment clinic (PAC) before major elective oesophagogastric surgery. Through a series of three QI cycles, we have treated iron deficiency, improved preoperative haemoglobin (Hb) and reduced the rate of postoperative blood transfusion. Our methods have included the early diagnosis of iron deficiency at the PAC attendance, the development and implementation of a new clinical guideline on the treatment of preoperative anaemia and the introduction of a one-stop clinic facilitating same-day treatment with intravenous iron, where appropriate, in conjunction with comprehensive preoperative assessment. The incidence of severe preoperative anaemia (Hb<100 g/L) has fallen from 10% in 2014 to 1.6% in 2018. The overall incidence of preoperative anaemia (defined as Hb<130 g/L by international consensus statement) has reduced from 57.9% in 2014 to 43.9% in 2018. Blood transfusion rate has declined from 16% to 6.5% of patients between 2014 and 2018. In 2018, none of the patients who required a postoperative blood transfusion presented to theatre with preoperative anaemia, a significant change from prior to the interventions. There has been a reduction of 63% in the number of units transfused. The project has successfully optimised these patients, leading to improved preoperative Hb and reduced use of blood transfusion.