Radiofrequency ablation (RFA) has been widely practiced to treat unresectable malignant liver tumors. It has the merits of localized tumor ablation and preservation of maximal normal liver parenchyma. In recent years, there has been a tremendous expansion in the application of RFA for patients with malignant liver tumors. However, the therapeutic effect of this local ablation treatment needs to be balanced against its risks and possible local failure. This review focuses on the current status of RFA for malignant liver tumors, with special attention to the indication, approaches, complications, survival benefits, combination therapies, and comparison with other treatment modalities. Although the results of most clinical studies of RFA seem favorable, the associated risks and tumor recurrence should not be underestimated. Careful patient selection, meticulous RFA techniques, and prompt treatment of residual and recurrent tumors are necessary to ensure a better outcome after RFA. Until recently, there has been no strong evidence showing that RFA can replace any other treatment modalities in the management of liver tumors. Nonetheless, more convincing evidence by randomized trials is required for the establishment of a treatment protocol of RFA for patients with malignant liver tumors.