Electroporation (EP) techniques, used alone (Irreversible Electroporation, IRE) or in combination with anti-cancer drugs (Electrochemotherapy, ECT), have been shown to be effective in the treatment of several types of cancers. The efficacy of ECT and IRE is well demonstrated for the treatment of non-superficial tumor metastases, and it depends on the applied electrical parameters. Particularly, ECT is an effective local therapy that uses electroporation to enhance the cytotoxic effect of bleomycin or cisplatin injected intravenously or intratumorally. Pre-clinical investigations to test alternative anti-cancer drugs, explore new combinations of treatment modalities, and evaluate different sets of pulse protocols for effective tissue electroporation, are ongoing. Further ECT developments include the treatment of deep-seated tumors with percutaneous, laparoscopy, and endoscopy approaches, with the aim of establishing a less invasive approach. ECT is highly effective in the treatment of tumors of any histology, in minimizing the damage of critical normal tissue or organs, and in reducing pain and muscular contractions. This work describes the new technological advances in the field of ECT treatment for deep-seated tumors.