To determine whether hypertonic saline (HS)-mediated bipolar radio-frequency (rf) application as advantages over monopolar simultaneous and alternating rf applications for creating larger areas of coagulation necrosis.A total of 60 rf ablations using double perfused-cooled electrodes and a 200W generator (CC-3 model, Radionics) were performed in three different modes in explanted bovine livers: simultaneous monopolar mode (groups A and A′); alternating monopolar mode (groups B and B′); or bipolar mode (groups C and C′). Electrodes were placed at inter-electrode distances of 3 and 5cm, and HS (6% NaCl solution) was instilled into tissue at a rate of 1mL/min through the electrodes. rf was applied for 10 (3cm distance) or 15min (5cm distance). During rf application, we measured the tissue temperature at the mid-point between the two electrodes. Dimensions of the thermal ablation zones, and temperatures were compared between the 3 groups using analysis of variance or the Kruskal–Wallis test. To compare configurations of the ablation zones in each group, the ratio of longitudinal diameter (D l ) to vertical diameter (D v ) was calculated.With a 3-cm inter-electrode spacing, the D v between the electrodes of ablated lesions was 2.4 ± 1.2cm in group A, 4.5 ± 1.0cm in group B, and 6.1 ± 0.9cm in group C (P < 0.05), and at a 5-cm spacing, groups B′ and C′ produced a single ablation area, but group A′ produced two separated ablation spheres: the D v s were 1.4 ± 0.2 in group A, 2.9 ± 1.0mm in group B, and 6.6 ± 0.4cm in group C (P < 0.05). For both 5- and 3-cm spacings, the temperatures at the mid-point were higher in bipolar mode than in either monopolar simultaneous or alternating modes. The ratios of D l /D v of groups A, B, and C were 2.5 ± 0.2, 1.4 ± 0.1, and 1.1 ± 0.1, respectively, and the corresponding figures of groups A′, B′ and C′ were 4.5 ± 0.2, 2.7 ± 0.1, and 1.1 ± 0.1, respectively (P < 0.05).HS-enhanced bipolar rf ablation creates larger, more regular coagulation necrosis than either monopolar simultaneous or alternating rf ablation.