Background The Australian and New Zealand Emergency Laparotomy Audit (ANZELA) perioperative protocol was implemented as standard-of-care for Emergency Major Abdominal Surgery (EMAS) at Bendigo Health in September 2021. ANZELA recommends all EMAS patients undergo routine preoperative risk assessment (RPRA) with the ‘National Emergency Laparotomy Audit (NELA) Calculator.’ Patients with NELA perioperative mortality estimates ≥10% are considered ‘high risk’ and routinely referred to the critical care unit (CCU) for planned postoperative admission. This study aims to identify whether RPRA and routine CCU referral for high risk EMAS patients are cost-effective interventions. Methods A retrospective audit was conducted including high-risk adult patients who underwent EMAS at Bendigo Health between September 2017 and August 2023. Postoperative outcomes and costs were compared before and after the implementation of the ANZELA perioperative protocol. A cost-effectiveness analysis was subsequently conducted to estimate the additional cost per improvement in outcome, presented as incremental cost effectiveness ratios. Results 191 high risk EMAS patients were identified. The mean postoperative cost of care was AUD$52,338.78, with no significant change post-ANZELA (p=0.98). Post-ANZELA, there was a 15.3% reduction in rate of planned CCU admissions (p=0.026), 10.9% reduction in rate of unplanned returns to theatre (p=0.045), and 16.8% reduction in rate of severe postoperative complications (p=0.03). There was no significant change in postoperative mortality (p=0.59). Conclusion The ANZELA perioperative protocol for high-risk EMAS improves perioperative outcomes without increasing costs. The protocol is therefore cost-effective.