Purpose Current guidelines recommend withholding sodium–glucose cotransporter 2 inhibitors perioperatively due to concerns of euglycaemic diabetic ketoacidosis. However, such guidelines are largely based on case reports and small case series, many extrapolated from non-surgical patients. The aim was to investigate whether withholding sodium–glucose cotransporter 2 inhibitors as per current perioperative guidelines was associated with a reduction in serious adverse events, including euglycaemic diabetic ketoacidosis. Methods Instances of perioperative management of sodium–glucose cotransporter 2 inhibitors, over a four-year period were classified into two categories: those where sodium–glucose cotransporter 2 inhibitors were withheld as per guidelines and those where sodium–glucose cotransporter 2 inhibitors were administered in the perioperative period. The primary outcome was ‘total major perioperative complications’: a composite of serious adverse events including euglycaemic diabetic ketoacidosis, diabetic ketoacidosis, acute kidney injury, urosepsis and death. Results Eighty-two instances in 64 patients were included. Withholding sodium–glucose cotransporter 2 inhibitors was associated with an increased incidence of total major perioperative complications and poorer glycaemic control postoperatively. Multivariable logistic regression analysis revealed that withholding sodium–glucose cotransporter 2 inhibitors perioperatively (OR = 13.15; 95% CI = 1.8–138.9) and preoperative urea (OR 1.85 (95% CI = 1.17–3.43) were independently associated with an increase in total major postoperative complications. Conclusion Withholding sodium–glucose cotransporter 2 inhibitors as per current guidelines was associated with an increase in postoperative complications and reduced glycaemic control.