Process parameters that could affect the emulsion droplet size during rotor/stator homogenization were investigated. The change of emulsion droplet size (EDS) was found to be kinetic, reducing initially and then reaching a constant, equilibrium value. The emul- sion droplet size decreased with increasing homoge- nization intensity using both the micro- and macro-tips. An ultimate equilibrium emulsion droplet size of around 1 /xm was obtained when the homoge- nization intensity exceeded 10 000 rpm with the macro- tip system. The EDS decreased with increasing viscosity of the continuous phase and with decreasing viscosity of the dispersed phase. Changes in the emul- sion volume ratio between the two phases showed no