The constitutive equation proposed by Phillips et al. [Phys. Fluids A 4, 30 (1992)] for shear induced particle migration in viscous flows of concentrated suspensions is used to calculate the change in viscous dissipation rate occurring when the particle distribution changes from a homogeneous state to the steady state. Four cases of simple unidirectional flows are considered. Two of these cases were discussed by Phillips et al. and are revisited here. In all cases, the expected decrease in the dissipation rate is found to be considerable. The degree of reduction in dissipation rate is influenced by whether the shear-induced migration is parallel or normal to the velocity gradient. ® 1994 American Institute of Physics.