This study determines the oncologic outcome of the combined resection and ablation strategy for colorectal liver metastases. Between January 1994 and December 2015, 373 patients underwent surgery for colorectal liver metastases. There were 284 patients who underwent hepatic resection only (Group 1) and 83 hepatic resection plus ablation (Group 2). Group 2 patients had a higher incidence of multiple metastases (100% in Group 2 vs 28.2% in Group 1; P < 0.001) and bilobar involvement (76.5% in Group 2 vs 12.9% in Group 1; P < 0.001) than Group 1 cases. Perioperative mortality was nil in either group, with a higher postoperative complication rate among Group 1 versus Group 2 cases (18 vs 0, respectively). The median follow-up was 90 months (range, 1-180), with a five-year overall survival for Group 1 and Group 2 of 51 per cent and 80 per cent, respectively (P = 0.193). Mean disease-free survival for patients with R0 resection was 55 per cent, 40 per cent, and 37 per cent at one, two, and three years, respectively, and remained steadily higher (at 50%) in those patients treated with resection combined with ablation up to five years (P = 0.069). The only intraoperative ablation failure was for a large lesion (≥5 cm). Our data support the use of intraoperative ablation when complete hepatic resection cannot be achieved.