Image-guided tumor ablation has become increasingly popular in recent years. While various percutaneous ablative techniques currently exist for the treatment but radiofrequency ablation (RFA) is currently the most widely used technique. To perform RFA needle electrode is inserted into tumor and emitted current producing local heat cells of a tumor at temperature above 50-60degC when cells die from protein coagulation and dehydration. Microwave ablation (MWA) is considered often to be capable of effective and controlled heating of large tissue volumes more than RFA. Aim of this study was to test the efficiency of RFA and MWA by numerical two-dimensional modeling of various kinds of microwave and radiofrequency electrodes. It has been developed mathematical model allowing comparing characteristics of heating of a homogeneous tissue by various electrodes. It's recognized time-dependent temperature's fields in tissue and influence of antenna's working part, levels of input power and frequency on process WA. Comparison WA and RFA showed that monopolar RFA does not allow to receive volumes of heating inherent WA. However application of cluster designs RFA allows receiving the results better than WA.