Internal mobilities of Li(+) and K(+) in the molten binary system (Li, K)Cl have been measured at (913 and 973) K. The product of the internal mobility and the modified molar volume has a constant value for Li(+) at 913 K and two constant values depending on concentration for Li(+) at 973 K and for K(+) at 913 K and at 973 K; the modified molar volume is the molar volume minus the deviation volume, appearing in an empirical equation previously presented. The present result is compared with that obtained for molten (Li, K)Br, which has previously been found to show a regular mode for the mobilities. The mobilities in the present system are attributable to the regular mode and, in addition, to the perturbed mode when the product has two values. The results are accounted for in terms of the dynamic dissociation model.