Introduction Thirty per cent of patients with colorectal cancer have metastatic disease at time of presentation, and a further 20% will develop liver metastases after the primary colorectal malignancy has been resected. Liver resection offers the prospect of cure for a proportion of these patients and, with the increasing use of effective neo-adjuvant chemotherapy, this proportion is increasing. However, liver surgery is associated with significant morbidity and mortality and this may be higher in patients with comorbidity, poor cardiorespiratory fitness and in those who have received neo-adjuvant chemotherapy.