Rheological behavior of emulsions has been investigated using a controlled stress rheometer while granulometrical investigation has been performed using an optical microscope and a Coulter particle size analyzer. The oil concentration was varied from 10 to 95 vol%. For low oil concentrations (from 10 to (60 %) ), a comparison of viscosity data with suspension viscosity models introducing the normalized oil concentration was carried out. Whereas for high oil concentrations (from 70 to (90 %) ), the cutting oil emulsions are characterized by viscoelastic behavior. The creep-recovery resuits are described very well by the generalized Kelvin-Voigt model in the linear region. The beginning of phase transition (\mathrm{O} / \mathrm{W}) to (\mathrm{W} / \mathrm{O}) agrees with the peak of viscosity and has been confirmed by the electrical conductivity data. Furthermore, the microscopic examinations reveal that the end of phase transition corresponds to the oil concentration of (95 %). The mean diameter and the size distribution of droplets have been obtained. An attempt has been made to correlate rheological and particle size results. (199.3 Academic Press, Inc.