Sedimentation in dilute suspensions of charged particles with thin double layers was investigated. The study covered sedimentation in polydisperse systems at a large Péclet number. The pair-distribution equation was solved by a regular perturbation method, and it was found that generally speaking the sedimentation coefficient deviates slightly from that at the infinitely large Péclet number except that the double layer was very thin. The results were found to pos- sess much more diversities than the case of hard spheres. Sedimentation in dilute suspensions of charged particles with thin double layers was investigated. The study covered sedimentation in polydisperse systems at a large Péclet number. The pair-distribution equation was solved by a regular perturbation method, and it was found that generally speaking the sedimentation coefficient deviates slightly from that at the infinitely large Péclet number except that the double layer was very thin. The results were found to pos- sess much more diversities than the case of hard spheres.