Radiofrequency ablation is considered safe for inoperable liver neoplasms; with small lesions the rate of success is very high, the local recurrence is marginal and generally suitable for a retreatment. We have little information about the possibility of rapid regrowth of the tumor after a response judged as complete. We present four patients, affected by primary (3 patients) and metastatic (1 patient) uninodular cancer. All the lesions were small, superficial and well suited for surgery, but were treated by radiofrequency ablation elsewhere. The early instrumental evaluations stated a complete result in all the patients. Cancer regrowth was diagnosed at 3, 4, 6 and 12 months after radiofrequency ablation, always starting from the treated lesion. In case 1 the whole right lobe was involved together with a controlateral multinodular recurrence; cases 2 and 3 presented an extensive liver and parietal wall involvement; while in the fourth patient a diffuse biliary colonization was observed. Only 1 patient was suitable for surgery; the others died 6, 2 and 4 months, respectively, after recurrence. Recurrence after radiofrequency ablation may show an aggressive evolution precluding any possibility of cure. Radiofrequency ablation must not be considered a suitable alternative to surgery in patients with a low surgical risk.