A non-colloidal particle suspension is studied in shear, and it is found that shear thinning takes place at a much higher Peclet number than in colloidal suspensions. In a steady shear-rate flow, the suspension viscosity increases and reaches a steady value when a critical strain is achieved. This critical strain is independent of the shear rate, and decreases with increasing particle concentration. It is proposed that the development of a shear-induced structure of particles, which grows when the shear rate decreases, is account for the increase of viscosity. The shear thinning in a non-colloidal suspension may not be due to Brownian motion, in contrast to colloidal suspensions. (C) 2015 Elsevier B.V. All rights reserved.