lThe sedimentation of concentrated charged spherical particles in an electrolyte solution is investigated theoretically for an arbitrarily thick double layer taking the effect of double-layer polarization into account. We show that the ratio E*/U* (=scaled sedimentation potential per scaled sedimentation velocity) is a constant if kappa a is either very small or very large, kappa and a being respectively the reciprocal Debye length and the radius of a particle. The variation of E*/U* as a function of kappa a has a minimum at a medium kappa a. This minimum increases with the increase in particle concentration. The scaled sedimentation velocity approaches a constant if kappa a is small, and its variation as a function of kappa a has a maximum at a medium kappa a. This maximum decreases with the decrease in particle concentration.