Irreversible electroporation (IRE) has recently gained in popularity as an ablative technique, however little is known about its oncological long-term outcomes. To determine the long-time survival of animals treated with a high dose of IRE and which histological changes it induces in tumoral tissue, IRE ablation was performed in forty-six athymic-nude mice with KM12C tumors implanted in the liver by applying electric current with different voltages (2000V/cm, 1000V/cm). The tumors were allowed to continue to grow until the animals reached the end-point criteria. Histology was harvested and the extent of tumor necrosis was semi-quantitatively assessed. IRE treatment with the 2000V/cm protocol significantly prolonged median mouse survival from 74.3±6.9 days in the sham group to 112.5±15.2 days in the 2000V/cm group. No differences were observed between the mean survival of the 1000V/cm and the sham group (83.2±16.4 days, p=0.62). Histology revealed 63.05%±23.12 of tumor necrosis in animals of the 2000V/cm group as compared to 17.50%±2.50 in the 1000V/cm group and 25.6%±22.1 in the Sham group (p=0.001). IRE prolonged the survival of animals treated with the highest electric field (2000V/cm). The animals in this group showed significantly higher rate of tumoral necrosis.