Enterococci are the focus of increasing academic and clinical research because of their importance as agents in nosocomial infections that are frequently refractory to many commonly used antimicrobial agents (1 –3 ). To facilitate studies on the pathogenic and drug resistance mechanisms associated with enterococcal infection, techniques for the efficient introduction of exogenous DNA have been developed. This chapter provides a description of a protocol used routinely to transform Enterococcus faecalis by electroporation. The efficient transformation achieved by this method results from the combined use of an agent to weaken the cell wall during the production of cells competent for electroporation and an osmotic stabilizer to preserve the integrity of the cell throughout the process.