BACKGROUND: Following abdominal surgery, postoperative ileus is a common complication significantly increasing patient morbidity and cost of hospital admission. This is the first systematic review aimed at determining the average global hospital cost per patient associated with postoperative ileus. METHODS: A systematic search of electronic databases was performed from January 2000 to March 2023. Studies included compared patients undergoing abdominal surgery who developed postoperative ileus to those who did not, focusing on costing data. The primary outcome was the total cost of inpatient stay. Risk of bias was assessed using the Newcastle-Ottawa assessment tool. Summary meta-analysis was performed. RESULTS: Of the 2071 studies identified, 88 papers were assessed for full eligibility. The systematic review included nine studies (2005-2022), investigating 1 860 889 patients undergoing general, colorectal, gynaecological and urological surgery. These studies showed significant variations in the definition of postoperative ileus. Six studies were eligible for meta-analysis showing an increase of €8233 (95 per cent c.i. (5176 to 11 290), P < 0.0001, I2 = 95.5 per cent) per patient with postoperative ileus resulting in a 66.3 per cent increase in total hospital costs (95 per cent c.i. (34.8 to 97.9), P < 0.0001, I2 = 98.4 per cent). However, there was significant bias between studies. Five colorectal-surgery-specific studies showed an increase of €7242 (95 per cent c.i. (4502 to 9983), P < 0.0001, I2 = 86.0 per cent) per patient with postoperative ileus resulting in a 57.3 per cent increase in total hospital costs (95 per cent c.i. (36.3 to 78.3), P < 0.0001, I2 = 85.7 per cent). CONCLUSION: The global financial burden of postoperative ileus following abdominal surgery is significant. While further multicentre data using a uniform postoperative ileus definition would be useful, reducing the incidence and impact of postoperative ileus are a priority to mitigate healthcare-related costs, and improve patient outcomes.