The preparation of concentrated aqueous silicone oil emulsions has been investigated with particular attention to the effect of the dispersed-phase volume fraction phi from 0.01 to 0.5 for a wide range of oil viscosities (50 to 1000 cSt). Oil was added on the top surface of a 6-L vessel. Drop size distribution and Sauter mean diameter, d(32), measurements were carried out over 24 h mixing time. Emulsification phi was found to be relatively sensitive to the oil phase Viscosity, mu(d), for the same phi yielding a narrower drop size distribution for low oil viscosity (50 cSt) and a wider drop size distribution for the highly viscous oil (1000 cSt). For the same phi, increasing mu(d) resulted in increasing d(32). The equilibrium d(32) was found to be well correlated to the viscosity number by d(32)/D = 0.026 * V-i(0.204) for phi = 0.5. For the same oil viscosity, d(32) was found to increase with increasing phi. A multiregression of d(32) with both phi and V-i for various silicone oil viscosity grades was successfully correlated by d(32) (=) 9.6 phi V-0.069(i)0.216 with a regression coefficient (R-2) of 0.975. This shows a very weak dependence of the equilibrium d(32) on phi.