Second-generation radiofrequency ablation (RFA) probes and their successors have more power, shorter ablation times, and an increased area of ablation compared with the first-generation probes used before 2000. We examined whether the use of the newer probes has improved the clinical outcome of RFA for hepatic metastases of colorectal cancer at our tertiary cancer center. Of 160 patients who underwent RFA between 1997 and 2003, 52 had metastases confined to the liver: 21 patients underwent 46 ablations with the first-generation probes and 31 patients underwent 58 ablations with the newer probes. The two groups had similar demographic characteristics. At a median follow-up of 26.2 months, patients treated with the newer probes had a longer median disease-free survival (16 months vs 8 months, P < 0.01) and a lower rate of margin recurrence (5.2% vs 17.4%); eight patients had no evidence of disease and one patient was alive with disease. By contrast, of the 46 patients treated with the first-generation probes, 2 patients had no evidence of disease and 1 patient was alive with disease. Newer-generation probes are associated with lower rates of margin recurrence and higher rates of disease-free survival after RFA of hepatic metastases from colorectal cancer.