In a flowing suspension particles migrate due to shear. This migration involves movement of particles perpendicular to the stream lines of the flow. When the suspension flows in a closed channel, particles drift from regions of high shear, usually near the walls, to regions of low shear, generally near the main axis of the channel, and accumulate there. The changes in particle concentration affect the local effective properties of the suspension, causing changes in velocity and concentration profiles in the channel.A dynamic model describing the particle migration was solved. In this model the flux of particles was calculated using gradients of particle concentration, of effective viscosity and of shear magnitude. The solution was based on the assumption that a fully developed velocity profile exists for every location along the flow channel. The results of the calculation gave the expected velocity, concentration and flux distribution in flowing suspension.The migration of particles was measured using laser Doppler anemometry (LDA). A measurement system was developed to enable the use of LDA for velocity measurements in highly concentrated suspensions. Velocity profiles in the direction of the flow and perpendicular to the stream lines were obtained. The profiles measured were similar to those expected from model calculations.