Mono-dispersed droplets were produced in different liquid/liquid systems using high frequency AC fields (30 kHz and 45 kHz), with voltages up to 20 kV. The dispersion of toluene and isododecane in distilled water, as well as the reverse dispersion type. were studied at 298 K. In particular, the influence of the applied voltage, AC frequency. flow rate and capillary geometry on droplet size were investigated. If the organic solvents are dispersed in distilled water, mono-sized droplets down to 90 mum were formed and controlled over a wide range of diameters, whereas the droplet diameter depends mainly on the applied AC voltage and the capillary geometry. The opposite dispersion type indicates a strong influence of dispersed phase conductivity on the droplet formation process, whereby with lower conductivity a deformation of the liquid surface at the capillary tip occurs. This unstable condition changes with increasing conductivity which results in a stable cone-shaped liquid surface with a liquid spray ejected from the edge of the cone.