A theory of sedimentation in a concentrated suspension of spherical colloidal particles proposed by Levine et al. (J. Colloid Interface Sci. 57, 424 (1976)) is further developed to derive a simple convenient expression for the sedimentation potential applicable for low zeta potentials and nonoverlapping electrical double layers of adjacent particles. An Onsager relation between the sedimentation potential and electrophoretic mobility of spherical colloidal particles in concentrated suspensions is derived.