Drug and gene delivery by electroporation is gaining increasing momentum, in particular delivery of chemotherapeutic agents (electrochemotherapy) is now routinely used in many cancer centers, and gene therapy is in clinical trials. Gene therapy using electrotransfer offers the possibility to create a localized area hosting the transgene, with possibility for (1) local effects on tumors, (2) systemic effect through local activation of the immune system, or (3) local production of the transgenic protein followed by secretion to the systemic circulation, where these drugs may exert desired effects on cancer cells, and/or on supportive structures such as blood vessels. An increasing amount of knowledge is accumulating on important pathways for cancer progression, and this allows discovery of new targets for cancer therapy. Gene therapy offers an easier and less expensive strategy for therapy, since DNA may be produced more easily than formulation of protein drugs, enabling a higher level of access to new potential drugs. Many cancer gene therapy clinical trials are ongoing at this time, and it will be very interesting to follow the clinical results. This chapter reviews the progress in drug and gene electrotransfer, describes the details of the procedure, as well as offers the perspectives for this technology.