Over the past decade, steric stabilization has been achieved for a variety of inorganic and organic colloids. in supercritical fluid carbon dioxide (SCCO2). Herein we demonstrate that colloids may also be stabilized in CO2 by electrostatic forces, despite the ultralow dielectric constant of 1.5. Zeta potentials of micrometersized water droplets, measured in a microelectrophoresis cell reached -70 mV corresponding to a few elementary charges per square micrometer of droplet surface. This degree of charge Was sufficient to stabilize water/CO2 emulsions for an hour, even with water volume fractions of 5%. Hydrogenions partition preferentially, relative to bicarbonate ions, from the emulsion droplet to,the cores-of surfactant micelles in the diffuse double layer surrounding the droplets. The micelles, formed with a low molecular weight branched hydrocarbon surfactant, prevent ion pairing of the hydrogen counterions to the negatively charged emulsion droplets. Dielectrophoresis of the water droplets at a frequency of 60 Hz leads to chains containing a dozen droplets with lengths of 50 mu m. The ability to form electrostatically stabilized colloids in carbon dioxide, is particularly useful in practical applications, because steric stabilization in CO2 is often limited by the poor solvation of the stabilizers.