Background Surgical resection of colorectal liver metastases (CRLMs) is the standard of care when possible, although this strategy has not been compared with non-operative interventions in controlled trials. Although survival outcomes are clear, the cost-effectiveness of surgery is not. This study aimed to estimate the cost-effectiveness of resection for CRLMs compared with non-operative treatment (palliative care including chemotherapy). Methods Operative and non-operative cohorts were identified from a prospectively maintained database. Patients in the operative cohort had a minimum of 10 years of follow-up. A model-based cost–utility analysis was conducted to quantify the mean cost and quality-adjusted life-years (QALYs) over a lifetime time horizon. The analysis was conducted from a healthcare provider perspective (UK National Health Service) in a secondary care (hospital) setting. Results Median survival was 41 and 21 months in the operative and non-operative cohorts respectively (P < 0·001). The operative strategy dominated non-operative treatments, being less costly (€22 200 versus €32 800) and more effective (4·017 versus 1·111 QALYs gained). The results of extensive sensitivity analysis showed that the operative strategy dominated non-operative treatment in every scenario. Conclusion Operative treatment of CRLMs yields greater survival than non-operative treatment, and is both more effective and less costly.