Electric, magnetic and electromagnetic fields have a wide application in medicine for both therapy and diagnostics. In oncology several treatments have been developed on specifically exploiting the characteristic interaction of electric, magnetic and electromagnetic fields with tissue. Electroporation, thermal ablation and hyperthermia are treatments that are used alone or in combination with the existing treatments. Irreversible electroporation and thermal ablation can be used as a single treatment and induce direct cell killing through permanent permeabilization of the tumor cell membrane or by killing the tumor cells by coagulating at high temperatures (>50°C for 4-6 min.), respectively. Hyperthermia and electrotrochemotherapy are, in contrast, always applied as part of a multi-modality therapy. Both hyperthermia and reversible electroporation are used to sensitize tumor cells for radiotherapy and/or chemotherapy. The combined treatment results in an enhanced effectiveness. i.e. increased cell kill, of the (hypoxic) tumor cells that are not killed by radiotherapy or chemotherapy.