Sheer viscosity of ceramic injection molding mixtures is predicted using the viscosity equation presented by Poslinski et al. (1988) for concentrated suspensions, The model was modified by taking into account the effects of the temperature and particles agglomeration on the viscosity. Alumina (Al2O3) and zirconia (ZrO2) powders were used for this study, The mean diameters of these powders are 0.5 and 0.43 mum, respectively. Low density polyethylene was used as a primary binder, and the powder was kneaded with the binder at a high solid concentration, The shear viscosity of the mixture was measured at various temperatures using a dynamic viscometry method with a cone and plate viscometer, The shear viscosity model presented in this study predicted well the viscosity data for non-agglomerated (Al2O3) and agglomerated systems (ZrO2) of the molding mixtures.