Appropriate electric pulses can reversibly permeabilize living cells both in vitro and in vivo. Since the pioneering work of E. Neumann and colleagues (1 ), cell electroporation (also often termed cell electropermeabilization) has become the most frequent method for cell transfection. Indeed, it easily applies in vitro to bacteria, yeast, animal, and plant cells. In vivo, the use of the DNA electrotransfer method is rapidly expanding because of its simplicity and efficiency. First attempts to transfer DNA in vivo to muscle cells were published in 1998 (2 ,3 ). This led in 1999 to an extended study on the determination of optimal conditions for DNA electrotransfer in skeletal muscle in mice, rats, rabbits, and even primates using a reporter gene (4 ). The same year, the first “therapeutic” gene (the erythropo�etin gene) was transferred to mouse muscle in vivo by Rizzuto and colleagues (5 ). In the last 2 years, several publications have used the conditions described in ref. (4 ) and have shown the wide applicability of this method for the electrotransfer of a large number of genes in different muscles (6 -8 ). DNA electrotransfer to skeletal muscle could lead to broad potential applications in the therapeutic field (metabolic disorders correction, vaccination, systemic secretion of angiogenic or antiangiogenic factors, etc.) and for physiological, pharmacological, and developmental studies.